Need Help Balancing High Tech System


New Member
May 18, 2019

Pictures Below.

75 gallon heavily planted, Co2 system, 3/4th EI dosing, 50% weekly WC, 2x Fluval 3.0 running at 80% for 8 hours a day, PH 6.6, KH 4.0( maybe 4.5), slightly light green drop checker, some surface agitation, sera 500 reactor. Co2 cranked up to uncountable bubbles per second.

Yet I still have some plant problems, such as black beard algae, staghorn, and some plants just arent doing too well while others are growing like weeds.

Long Version -

Hi! I'm Shan and I would really appreciate help after 2 months of trying to balance my aquarium and failing. ><

I recently invested in my first tank, a 75g heavily planted tank with quite a bit of fish and plant load. I think im stocked around 90%. I'm running everything mentioned above with a cascade 1200. I fishless cycled my tank prior to putting in any fish. All fish seem super happy and have been, but the plants have given mw mixed results.

My goal is to balance my aquarium to having 0 algae, beautiful red and lush green plants, and possibly lowering my co2 intake (unless that sacrifices my plants.)

I have read that staghorn and BBA is a co2 related problem, but cranking it up hasn't helped as much.

As you can see from the pictures, even though alot of plants have exploded in growth, I've had a lot of trouble battling some algae and getting my CO2 ppm high. From reading around the forums the past few weeks I've found out that i should keep upping my co2 until I notice a change in fish behavior. I have it cranked up quite a lot but ive never seen any change in behavior from my fish. I also cannot get my PH below 6.6. (My KH is 4)

I feel that I shouldn't have to crank the co2 up this much to get a nice balance. I have algae that shows up on my glass sometimes, tons of snails, and various algaes that show up on random plants form BBA on swords, to staghorn on wood.

I would be happy to share or answer any questions that would help me figure out how to balance my tank. I understand I should be doing small changes and watching it, so I know it will be a slow process to balance. Currently I am trying to lower surface agitation to attempt to keep more co2 in the tank. 3 weeks ago I lowered my EI dose to 3/4th recommended and have not noticed a change.

P.S. I have reduced surface agitation as of this morning, and was able to get my PH down to 6.5, but I'm still blasting CO2. I don't want it to be wasteful.





Last edited:


Lifetime Charter Member
Lifetime Member
Jan 15, 2009
A good target is roughly a 1 pH drop from degassed to full CO2 on. i.e. pH in the morning before CO2 on of say 7.6 and then 6.6 at full CO2 saturation. That should give you a reasonably decent CO2 level and should be an easy target.

Try measuring your pH and see how much of a drop you can get with your current injection method. Back off your CO2 until you just start to see a smaller pH drop. Most likely you are just wasting CO2. You may need to tweak your injection method.

You may have too little or too much flow in the areas with BBA. Consider one of the propeller pumps to get some additional water movement. That may also help with your CO2 diffusion overall.