I have a drop checker yes..... BUT I NEVER use it to tell me how much Co2 I have or if I have enough. There is no real way (well Affordable way for hobbyist) to fully and accurately measure the Co2 levels. Not with a drop checker or a PH monitor. In fact PH monitors dont measure anything to do with Co2 PPM. All they measure is PH level and change the Co2 amount based on PH. Problem with that is that Various things can effect a persons PH in their tank. KH and GH for instance. Not every ones water will have equal KH and GH so the readings you get for one tank vs the next will be different BUT yet with the tank that has higher KH and GH your probably adding twice as much Co2 to get the PH to move vs lower KH and GH.
The Issues with drop checkers are they arent even close to 100% accurate. I wouldnt even classify them as 75%. According to the color of my drop checkers my fish should be dead as it always runs bright yellow. But yet I have zero fish issues. Also Drop checkers are very slow to respond. mine takes 2 hours at least to reach full color change. In some cases your fish will show issues in 30 min to an hour. Next thing you know your gassing your fish but drop checker shows good. Alot of things can effect drop checkers as well. Placement, current, if the Co2 is highly dissolved vs lots of free floating bubbles (reactor vs Atomizer) KH of the water and a few other things.
I think alot of times we try to put a number on something with PPM of Co2. The 3 key things that should tell you if you have enough Co2 or not is this..
First your fish. If your fish are gasping rolling over and being gassed by the Co2 that of course we know is bad so we know we need less Co2. This should be the first thing we use. Adjust your levels keep increasing until you end up with a fish issue. Once you start to see your fish behaving odd and needing air back off the co2 to a safe level where your fish are fine. Let your drop checker reach its color. This will help you calibrate your drop checker for whats good along with the MAX Co2 level. At this point it wont matter what PPM you have. If your low in PPM you cant add anymore or you kill the fish. So PPM isnt important.
Second. Plants should help tell you as well. If you have happy plants, good nutrients and plenty of lights you should end up some pearling. Even if no pearling colors and growth should be matched to light and nutrient input.
Lastly Algae, Most all issues with Algae are related to low or inconsistent Co2 issues. Some are about low nutrients and such but alot of it really boils down to Co2.
Ive got my tanks dialed in. No Fish issues, GREAT growth daily, With pearling and awesome color. NO Algae issues. So this is how I measure.
BPS is another measurement we use that should get thrown out the window as well.. But thats a whole different discussion.
My 20 gallon and 29 gallon planted tanks each use 8bps, While my 46 uses 10 to 15 bps, and my 90 uses 10bps X 2. As it has 2 reactors. Id bet your 150 gallon could use more then the 5bps your using now. Especially having a wet dry sump.
