Alkalinity swings when adding saltwater

[Duds]

Hey all,

I have a 10 gallon with 1.5" sand bed, roughly 15lbs of live rock which makes its volume roughly 8 gallons. The tank has been running perfectly other than alkalinity after doing a water change (haven't done one in almost two weeks) or adding saltwater after acclimating a new fish/invert/coral. My target alkalinity is 8.5dkh (or was). I keep a log of everything done and tested in the tank so I'm going to list things done recently to show examples of what has been happening, and what I have done and tested as a result. Temp 78 degrees Fahrenheit and salinity between 1.025-1.026.

10/14 I bought rodi water I was using tap and was having some algae problems i contributed to that. So I did a 50% water change, at the time I did not have an alkalinity test kit it came in the mail on the 16th. Ph before was 8.0 the following day was 8.2 seemed good to me.

10/16 Salifert test kits came in the mail alkalinity tested at 6.4 dkh read you can dose upto 1.4dkh per day to raise alk on top of coral consumption so dosed accordingly and brought the alk to 7.8dkh, ca over 500ppm, mag 1200ppm.

10/17-10/20 Alk 7.7dkh dosed accordingly to bring to my target 8.5dkh consumed .7dkh per day (I was dosing once per day)

10/21 Did a 20% water change as it was a week from my last one and wanted to try and get my magnesium up before alk was 7.7dkh after it was 6.7dkh so dosed to bring upto 8.3dkh little higher than i meant to but only zoas for corals in the tank and they were unaffected.

10/22 Alk was 7.3dkh dosed to bring to 8.5dkh (upto this point I was using red sea coralline gro as my alk supplement)

10/23 Alk 7.3 dosed to bring to 8.5dkh mag 1170ppm (read can raise 100ppm per day) dosed accordingly 1270ppm (at this point I knew I was getting hard corals soon so stopped use of coralline gro and started with red sea liquid foundation kit abc as needed)

10/24 Alk 8.3dkh dosed to bring to 8.5 mag 1270 dosed to try and bring it up only 100ppm but it went up 150ppm (I added frogspawn, hammer, candy cane, duncan, monti spongodes, monti digi (german blue and forest fire).

10/25 Alk 8.0dkh dosed to bring to 8.5dkh frogspawn and hammer look a little shrunk

10/26 Stayed stable frogspawn and hammer still not happy alk 8.5, ca over 500ppm, mag 1440ppm climbed a little??

10/27 Alk 8.1dkh dosed to bring to 8.5dkh mag dropped to 1380ppm dosed to try to bring it upto 1400ppm but it went to 1440ppm Ca still over 500ppm but can tell its dropping

10/28 Alk dropped to 7.8dkh dosed to bring back up now 8.6dkh mag 1390ppm ca 500ppm

10/29 Alk 8.3dkh dosed to bring to 8.5dkh (at this point I started dosing max .4dkh at a time to prevent shocking corals) so checked multiple times throughout the day it dropped again at night to 8.3dkh and doseed to bring back to 8.5dkh

10/30 Alk stayed stable all day at 8.6dkh with no dosing ca still over 500ppm didnt test mag

10/31 Alk 8.7dkh no dosing done

10/31 Tested original IO salt: alk 3.5dkh, ca over 500ppm, mag over 1500ppm;
Bought a bag of reef crystals and another IO regular since it tested so low hence my drops in alk after top offs or water changes.
Reef crystals: alk 13.1dkh, ca way over 500ppm, mag over 1500ppm
Second bag of IO: 10dkh, ca 450ppm, mag 1305ppm

10/31 topped up with new IO regular salt with 10dkh after adding a fish over the weekend to bring upto the right level and the alk raised to 9.3dkh, ca still over 500ppm mag 1440ppm (it was a small top off shouldn't have raised it like this so confused with that but thats not really the main concern, I talked to a few others and was recommended trying to match the tank alkalinity to the salt alkalinity so my new target was 10dkh)

11/1 Alk 9.3dkh all day till about midnight then dropped to 9.0dkh so dosed again to bring raise max of .4dkh a day to 9.4dkh (new target of 10dkh dosed only to raise .4dkh as to not shock corals not actively trying to raise to 10dkh as still not sure what to do)

11/2 Alk is 9.9dkh (not sure how it increased again over night without dosing and with retesting after dosing it shouldnt have gone up from the 9.4 if anything gone down with consumption but again not major concern more worried about when i add saltwater to my tank) I was told my salt would not mix the same each time so did an experiment and it was right the second io bag tested to 11.5dkh instead of the original 10dkh. Now my head really hurts.


So if you have followed this far a long I am curious of your recommendation for adding saltwater to my tank after acclimating a new coral, fish, or inverts or even a water change if need be down the road. I am trying to avoid fluctuations in my alkalinity as ive lost some corals already due to it I believe. Do I have bad salt or should i try another brand or do i need to dose to raise/lower my alkalinity in my new batches of saltwater to match my target/tank alkalinity prior to adding to the tank to prevent swings? And since my alk is up at 9.9dkh should i just target a higher alk like 10dkh to not keep annoying things?

Any advice help or insight is greatly appreciated as I'm just about at a loss other than testing every batch of saltwater i make then dosing accordingly which seems a bit over the top to me. My duncan, candy cane, bambam zoas, and vampire in drag zoas are doing well and growing by the looks of it the only other coral I have but isnt happy is the frogspawn and i would assume due to the swings. Everything else other than adding saltwater is perfect things stay stable in between saltwater top offs then one comes along and it tanks or spikes.

Thanks
Stephen

 

[Waterman1]

I always match my tanks alk with the salt I’m using! So if my salt mixes at 9 when i do a water change I keep my tank around 9 the best I can and dose to do so. If you want a higher alk or lower you could change your salt to a brand that has either

 

[Duds]

I always match my tanks alk with the salt I’m using! So if my salt mixes at 9 when i do a water change I keep my tank around 9 the best I can and dose to do so. If you want a higher alk or lower you could change your salt to a brand that has either

There in lies my problem my first bag of regular io salt I tested was 3.5dkh then second bag of regular io i tested the first time was 10dkh the second time I tested the same bag same temp and salinity i tested it was 11.5dkh at the same time as grabbing the second bag of io I grabbed a reef crystals and that resulted in 13.1dkh.

My original target number was 8.5dkh but with the salts listed above that’s not possible unless I dose the batch before adding to either drop or raise the alk quite significantly. And on the flip side the numbers are either a bit too high than I’d really like to run or deathly low but even more so they are inconsistent batch to batch in the same bag as I only have a 10 gallon tank I make only what I need I don’t have a mixing station just buckets and a spoon lol.

 

[Waterman1]

I shoot for 8.5 to I use redsea blue bucket and they are usually all pretty close to that and also depends on what your using to test for alk could be giving you different numbers

 

[Cpage101]

stop aiming for a specific # anywhere between 8-9dkh is fine.It will fluctuate, try to test at the same time every day also when testing alk as it is consumed over the days time. morning is best imho

 

[Duds]

I shoot for 8.5 to I use redsea blue bucket and they are usually all pretty close to that and also depends on what your using to test for alk could be giving you different numbers

Your the second person that has said Red Sea blue bucket and that it pretty consistently tests 8.5. I’m using all Salifert test kits seem to be a good goto still

 

[Duds]

stop aiming for a specific # anywhere between 8-9dkh is fine.It will fluctuate, try to test at the same time every day also when testing alk as it is consumed over the days time. morning is best imho

Honestly I’m not trying to but I add saltwater after a new addition and my alk drops or raises drastically because of the salt mix I’m adding to the tank being either too high or too low from my “target” number/tank number. I get the consumption I’m good with that tank runs perfectly until I have to add water after adding a new specimen whatever it may be. Then adding new saltwater alk swings like crazy and most don’t appreciate that at least hard corals.

 

[Skmaiden]

- The original IO salt was likely old - discard it and use new. Shouldn’t be a long term problem.
- Consider using a salt with alk generally inline with your target. Reef Crystals typically has a higher alk so you don't need to dose much but with say 11dkh, a 25% water change would increase your target 8.5dkh to approximately 9.1dkh. This is not necessarily terrible though is something you probably should account for when also dosing (ex. lesser dose after w/c or could produce large alk spike).
- Not 100% on the chemistry but typically alk doesn't increase by itself without w/c or dosing. You can find some causes why it would discussed online though I’d first double check you’re doing the test accuracy and consistency.
- A few dkh range is fine, just keep it generally consistent. Salt mix dKHs arnt always consistent but are usually similar. Having a 10 or 11.5 dkh salt mix doesn’t really make much of a difference in talk alk during a water change. I typically measure alk every few days with a doser set to daily dose enough alk to replenish the amount consumed though recognize that alk consumption isn’t always consistent. So while I’m consistent in dosing, alks still going to swing a bit as consumption still varies

 

[Duds]

- The original IO salt was likely old - discard it and use new. Shouldn’t be a long term problem.
- Consider using a salt with alk generally inline with your target. Reef Crystals typically has a higher alk so you don't need to dose much but with say 11dkh, a 25% water change would increase your target 8.5dkh to approximately 9.1dkh. This is not necessarily terrible though is something you probably should account for when also dosing (ex. lesser dose after w/c or could produce large alk spike).
- Not 100% on the chemistry but typically alk doesn't increase by itself without w/c or dosing. You can find some causes why it would discussed online though I’d first double check you’re doing the test accuracy and consistency.
- A few dkh range is fine, just keep it generally consistent. Salt mix dKHs arnt always consistent but are usually similar. Having a 10 or 11.5 dkh salt mix doesn’t really make much of a difference in talk alk during a water change. I typically measure alk every few days with a doser set to daily dose enough alk to replenish the amount consumed though recognize that alk consumption isn’t always consistent. So while I’m consistent in dosing, alks still going to swing a bit as consumption still varies

Anything more than a .4dkh difference at a time and my corals get unhappy. I am only working with 8 gallons. So say I need to replenish a gallon of saltwater after an acclimation that’s 12.5% of my water volume off the bat. So adding in 10-11.5dkh saltwater to my “target” 8.5dkh tank water like you said will make it spike. Which in my short experience with this tank it doesn’t like that much of a swing. I get what your saying that I should be able to just add the water and the corals consume it over a few days. However that is how my hammer died and when I just topped off the other day with 10dkh it raised to 9.3dkh in my tank now my frogspawn is having a rough time again and that was an increase of .6dkh.

 

[Skmaiden]

Anything more than a .4dkh difference at a time and my corals get unhappy. I am only working with 8 gallons. So say I need to replenish a gallon of saltwater after an acclimation that’s 12.5% of my water volume off the bat. So adding in 10-11.5dkh saltwater to my “target” 8.5dkh tank water like you said will make it spike. Which in my short experience with this tank it doesn’t like that much of a swing. I get what your saying that I should be able to just add the water and the corals consume it over a few days. However that is how my hammer died and when I just topped off the other day with 10dkh it raised to 9.3dkh in my tank now my frogspawn is having a rough time again and that was an increase of .6dkh.

Everything is percentages. A 20% water change on a 10g or 100g tank will result in the same change. If you’re doing a 4g w/c on a 10g, thats probably around 50% of the water replaced. Changing 2g water at a time is probably a good number. What do you mean “topped off”? Topoffs should be fw, w/c salt.

Few questions:
- Do you have an ATO/how is salinity maintained?
- what other parameters do you test/monitor? What makes you certain its the alk that the corals aren’t liking?
- do you need to dose? With mostly soft coral and limited lps, you may be ok with just reef crystals. Many people don’t dose and their tanks are fine with some ak fluctuations which is why im questioning if you’re certain its the alk. And not something else

Suggestions:
- see if you can pick up a couple cheap BRS or other dosers to automate dosing. Set on a timer for a few times a day vs all at once. If your alk drops 0.7dkh per day, you’re almost guaranteed swings at least that by dosing once per day. Even manual doing 2x a day would help reduce the swings.
- matching w/c temp and salinity is more important than alk so make sure these are consistent

 

[Duds]

Everything is percentages. A 20% water change on a 10g or 100g tank will result in the same change. If you’re doing a 4g w/c on a 10g, thats probably around 50% of the water replaced. Changing 2g water at a time is probably a good number. What do you mean “topped off”? Topoffs should be fw, w/c salt.

Few questions:
- Do you have an ATO/how is salinity maintained?
- what other parameters do you test/monitor? What makes you certain its the alk that the corals aren’t liking?
- do you need to dose? With mostly soft coral and limited lps, you may be ok with just reef crystals. Many people don’t dose and their tanks are fine with some ak fluctuations which is why im questioning if you’re certain its the alk. And not something else

Suggestions:
- see if you can pick up a couple cheap BRS or other dosers to automate dosing. Set on a timer for a few times a day vs all at once. If your alk drops 0.7dkh per day, you’re almost guaranteed swings at least that by dosing once per day. Even manual doing 2x a day would help reduce the swings.
- matching w/c temp and salinity is more important than alk so make sure these are consistent

When I said "topped off with 10dkh" I meant replenished saltwater and was saying i was using the second bag of io salt. That was after acclimating a new fish over the weekend not topping off from evaporation, that is done with fresh ro/di water.

- I do not have an ato yet I have been in talks with a member to buy one, salinity is maintained by a refractometer.

- I test most things everyday if something looks off, but just from talking to others and discussing what has been happening everyone has been saying alk swings. CA is over 500ppm just about 500 now (calcium burn?), mag at one point was over 1400ppm but ive heard of others running high mag with no adverse affects, i did not have much for nitrates so added a fish over the weekend the old school way and now i have about 2ppm of nitrates, ph hovers 7.8-8.1 no ammonia no nitrites no phosphates that i can tell by salifert test kit they are all salifert test kits.

- That is all I have for now coral wise but I have plans to purchase a fair amount of coral from members ranging from softies, lps, and sps which i discussed prior to my other corals not doing so well hence my tenacity to get ahead of the problem.

- Dosing wise I was suggested to break it into multiple doses throughout the day if needed so that has been what I am doing. Dosing isn't the problem here I have not dosed it is when i add saltwater to my tank to replenish the saltwater removed for acclimating a new coral/invert/fish. After doing so my alkalinity either has dropped drastically(from the first bag of io salt testing to 3.5dkh) or raised too much (the second bag of io salt that has tested 10 and 11.5dkh) that has been when I noticed the problems.

- I have a couple spare heaters I throw in to heat the water up to temp then check the salinity I only recently thought about checking the saltwater from someone else's recommendation for alkalinity to see if that was causing my problem and it was but now I don't know how to correct it.

 

[Reefer508]

Have you done multiply tests to confirm results? I could test for you if you can swing by with a sample.

 

[Duds]

Have you done multiply tests to confirm results? I could test for you if you can swing by with a sample.

I have done multiple tests through my test kit and it results the same each time, I don't have another test kit to compare the results with. We will hopefully link up this weekend as my son is now home from school with a fever and its his birthday weekend with soccer, urban air, a sleepover with three friends and a 9lb brisket for the party on Sunday I'll be smoking through the night should be fun lol. Thank you!!

 

[Cpage101]

Honestly I’m not trying to but I add saltwater after a new addition and my alk drops or raises drastically because of the salt mix I’m adding to the tank being either too high or too low from my “target” number/tank number. I get the consumption I’m good with that tank runs perfectly until I have to add water after adding a new specimen whatever it may be. Then adding new saltwater alk swings like crazy and most don’t appreciate that at least hard corals.

are you adding salt water to top off from evaporation?

 

[Duds]

are you adding salt water to top off from evaporation?

No for evaporation I am adding fresh rodi. Sorry for the confusion my only issue is adding saltwater after using some to acclimate something. I don’t put the water from the acclimating back in my tank. I mix up some new saltwater to add back in but the alk difference in my salt mix makes my tank alk swing too much that my corals are unhappy. I just need to match my batch of saltwater alk to my tank alk that’s the only way that makes sense to me I can’t match my tank alk to a salt alk that does not mix consistently. Other than making a mixing station for most of the salt then matching the tank to it like that. So I know the alk is consistent for x amount of gallons and then once I have to make a new batch hope it mixes similarly lol.

 

[Cpage101]

so alk does deplete and you top off with rodi i did not go back and reread but what are you using for salt if it has elevated alk then there in could be the issue. I use brightwell neomarine then I test tank water then my mixed water then dose the mixed to match my current tank levels. My system runs 8-8.7 pretty consistent. I do run a calcium reactor so you would have to dose your tank to make up for depleted major 3 elements

 

[Duds]

so alk does deplete and you top off with rodi i did not go back and reread but what are you using for salt if it has elevated alk then there in could be the issue. I use brightwell neomarine then I test tank water then my mixed water then dose the mixed to match my current tank levels. My system runs 8-8.7 pretty consistent. I do run a calcium reactor so you would have to dose your tank to make up for depleted major 3 elements
View attachment 184440

Awesome thank you very much for your help!!! Those apex’s are pretty sweet maybe one day lol.

 

[Duds]

I figured I should update this with my latest findings. I bought my refractometer from petco and I always had my doubts on its accuracy. On Monday it broke on me while calibrating, so I went straight to hanna in Smithfield and bought a salinity tester. I cannot say enough positive and wonderful things about this tester. It is simple and easy to use no messing around just stick it in the water and you get a digital readout of your salinity and water temperature. And it comes with 4 packs of calibration fluid.

So anyway back to it I got the tester home and calibrated it and checked my salinity I had checked earlier at a supposed 1.026 and it was 1.022. So over the course of about 12 hours I slowly raised the salinity to 1.026. The frogspawn that looked rough is starting to make a recovery and everything is looking even better and happier.

On top of that I also grabbed a Red Sea blue bucket as I can’t help myself and it mixes just about 8.5dkh every time so I’m gunna use that makes life easier for me.

Thanks for all the help tips and suggestions along the way!

 

[Skmaiden]

Those hanna salinity checkers are great and make mixing so much quicker. I still have a Refractometer for periodic checking but use it very infrequently these days.

 

[SteveDola]

One thing to consider is confirming your test kit with either a second test kit or bring a sample to a LFS that does testing with reliable test kits. This will give you a second reading and independent confirmation of the reading. I would definitely look into a more reliable salt if yours is inconsistent from batch to batch. Even if you have a small tank, one large bucket will last longer but also be constant for the tank chemistry.

I ran a 15 gallon waterbox for about 2 years and would do a 2 - 3 gallon water change every Sunday and was very happy with the results. I started with IO salt due to the price but then decided to change to TM pro since the cost on a smaller tank was negligible. I also would always test the water prior to new bag IO batch water changes to confirm the measurement of ALK. Its been known that IO can vary. I honestly wouldnt worry about 10 dKH tho...it would only move the measurement of alk in the tank a .5 or so which isnt considerable. My eye brow would raise if the ALK was 14 dKH or 5 dKH (outlier of acceptable range). It sounds like youve taken the IO salt out of the equation but I would still continue the value checks on ALK just to be sure when changing salts or new buckets.