Cloudy after vinegar dose

[Sethjamto]

A little history on my setup. 90g display with 20g sump. Mostly softies and LPS with just one SPS. Parameters held fine for about 10 months, then alk and cal started dropping and water changes did not keep them up where they were in the early stages of the tank.

I started dosing 2 part by hand to slowly raise alk and cal successfully. After I got them stabilzed I started with kalk in my ATO at a rate of 2.5 tsp per 5 gals of RODI. I ran this for about a week and noticed that it wasn't quite enough to maintain alk and cal, so I'm at 3.5tsp per 5g RODI now and figure I'll need to go more as levels are still slowly dropping.

During a water test yesterday my pH was 8.5 and I figured it may be from the kalk dosing in the ATO. After reading on reefkeeping.com about vinegar dosing to help reduce pH (it recommended 1mL per gallon to reduce pH by 0.3), I cut that in a third and dosed 30mL of vinegar yesterday and 30 today. My tank is now starting to get cloudy a few hours after dosing and I'm sure its just a bacteria bloom.

So....should I just ride it out? Water change? Am I doing the vinegar properly? I didn't want to go with the full 1mL per gallon right off that bat.

My pH right now after the two 30mL doses back to back days is either 8.1 or 8.2 (using an API test kit and its always difficult to tell the colors apart...).

Also, aside from what to do now (if anything), how do I help to maintain everything in the future? Do I keep up with the kalk and also do a regimen of daily vinegar dosing too? If so, recommendations on how much a day?

[bertoni]

I'd skip the vinegar altogether, since the tank seems to be having problems with it, but the bacterial bloom might fade over time. I would reduce the dose a lot. For dosing limewater, up to 15 ml per gallon added to the ATO is the usual limit, and that's for full-strength lime. I'm not sure how much water evaporates from your tank each day.

pH at 8.5 is safe enough. Also, more aeration might help reduce the level quite a bit.

[Sethjamto]

I'm using BRK Kalk at a rate of 1/2tsp per gallon of RODI...not sure what that converts to in ml per gallon.

Understood that pH at 8.5 is safe, but at the upper end of the spectrum, no? Wouldn't it be better in the 8.1-8.3 range?

[Duvallj]

8.5 is ok, but I'd shoot for 8.3. If you keep needing to add kalk to keep up with alk/cal then your pH can get to unsafe levels. Aeration would help up the alk levels by reacting with co2 in the air.

I'd also skip the vinegar to use to lower pH. I'd back off of the Kalk to get pH around 8.1-8.3 range and 2 part to keep alk/cal incheck.

[bertoni]

I don't think you'll notice any difference between a pH of 8.5 and a pH of 8.3.