Tank in poor health

192clark

Premium Member
At one time I had a simple but beautiful tank. Then about a year ago I noticed a decline in my Frogspawn. My tank was covered with many large areas. Now most of the Frog spawn is dead. Everything including Live rock has a dull grey/brown color to it. My nitrates were high during the die off so I have installed a Sulfur denitrator and have the nitrates at 5. The denitrator lowers the ph. The ALK was very low so I began adding more ALK and checking every 3 days and add more ALK according to what the reef chemistry Calculator suggests I use Randy Holmes Farley's chemical supplement method. My ALK drops and using the ALK supplement I can keep that in range. My CA is at 590. Now I have stopped using the two part CA/ALK supplement and I am only using the ALK. Because the PH gets very low I have installed a CO2 scrubber in searching for ways to help my tank.

Tank 175 gal
Return : Panworld 50 PXX
Closed loop: Dart
3 X 250w DE Metal Halide
Large Warner Marine Protein skimmer 10"

I am starting to see a bit of Coraline Algae on the ( dead rock ?)

The fish are fine but this tank looks like a desert.

Any help/suggestions are Greatly Appreciated
 

Alex114

Member
What is your alk at? Calcium is pretty high. I would wait to add corals till that's down a little bit. Once your confident things are stable then slowly add some easier corals. I'm sure you've heard it before but stability is key. As soon as water changes stop being enough you should be dosing like you are to keep up with the corals. What kind of corals are you looking to get again as well?
 

192clark

Premium Member
My ALK is stable between 9-10. The tank was full of Frogspawn to the extent that I sold a 5gal bucket 3/4 full. So I want that to recover. I of course will wait that out. I am wondering if the fact that my ALK went low did that cause the Ca to shoot up. Can anyone comment about just dosing with the ALK and do you agree that in time will bring down Ca as the tank recovers
 

Alex114

Member
Yes, if you stop dosing calcium and just maintain alk the calcium will drop as coralline algae uses it up, as well as it getting taken out through water changes. Just a few weeks ago I accidentally stopped dosing calcium while still dosing alkalinity (just wasn't paying attention lol) and my calcium dropped from 460 to 425 in 7 days. Yours won't be that fast, my tank is full of sps and coralline but you get the idea. What would be worth checking is magnesium. If that's low it can really mess with calcium and/or alkalinity to my understanding
 
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