Who needs a skimmer?
I happened to pick up the Red Sea Marine Care test kit (ammonia, nitrite, nitrate, pH and alkalinity) as I had been curious what my pH typically runs at and I couldn't pass up the deal I got on the kit. I have noticed my tank was doing quite well and the growth has started to take off and I have been doing a little bit or research that says higher pH leads to better growth. Basically there's carbonate and bi-carbonate molecules in the water and the only difference is bi-carbonate has a hydrogen molecule attached to it's structure. These two molecules constantly change in the tank (dropping and picking up the hydrogen molecule).
Corals need calcium and carbonate (no hydrogen) to make their structures so one would assume they prefer to take in carbonate over bi-carbonate. If they take in bi-carbonate they have to expend energy kicking off the extra hydrogen molecule. Lower pH tanks have more free hydrogen molecules so in theory there's more free hydrogen molecules floating around so there's more bi-carbonate molecules in the tank. Higher pH means less free hydrogen molecules in the water so there's more available carbonate which means less energy expended by the corals so they can grow faster.
Anyways due to the corals growing much faster lately I had been wanting to test my pH to see what my my pH is at now to see if part of the reason for the faster growth could be due to a higher pH. I am only running a HOB refugium (about 3-4 gallons on my 25'ish cube) on a reverse lighting schedule (10pm-10am). Ever since I took the skimmer out when I went with a HOB refugium I was wondering what the pH of the tank would be because it's normally agreed that a skimmer will increase the pH of a tank. Since I don't have a controller I don't have instant trackability of pH to see the swings which is why I wanted to test it. I tested the tank this morning at around 7am with just the refugium lighting on and the pH was 8.2 which I was pleasantly surprised about. I wanted to test the pH during the 30-45 minute overlap when the DT lights are on at the same time but wife was teaching her class on Zoom in the room where the tank lives so I couldn't check.
I tested again at 11:30am when just the DT lights were on and at about 2/3 their scheduled highest setting. I plan to retest after 3pm as that's when the DT lights are set the highest. At 11:30am the pH was 8.1. I rushed the testing due to having limited availability to the tank which could be why it went down.
For the hell of it I also tested the ammonia and nitrites and they were at zero. Alkalinity was at 8 dkh and then 7.8 dkh on the other Red Sea kit that has a much finer testing ability. Calcium was at 380 with Magnesium being at 1320. Calcium has been constantly around 380 for a while (benefits of keeping a list and monthly testing log) while the alkalinity has been closer to 8.5-8.7 dkh so I will be adding a few more milliliters of 2 part daily. Makes sense as faster/better coral growth means the tank will use up more calcium and alkalinity.
My biggest surprise was my nitrates were below 2 ppm and I would have said they were 0 actually. I thought my tank would have much higher nitrates due to having 6 fish in about 28 gallons of volume (probably closer to 25 with rocks and sand) with very heavy feeding. I feed at least a whole cube of food daily as well as baby brine shrimp daily and I'm starting to do daily phyto dosing. All this without having a skimmer on the tank and only doing water changes every 2'ish weeks with NSW and the windows have been closed due to the wife being a baby and doesn't like the cold so I was pleasantly surprised on many levels...