Alkalinity swings in pico tank

[reefer_madness_01]

I set up my little 3 gallon PiCo tank a few months ago and haven't done much other than let it cycle, add a CUC and a couple tiny frags of zoas, pulsing xenia and a tiny chunk of pocilopora from my 150 just because.

I feed my CUC a bit and have been changing out about 1 gallon of water every week and have some chemipure elite in the back chamber (maybe 2 oz). I finally have the time to devote more energy to this tank and have began testing calcium and alkalinity to see where I am at. I would expect almost no fluctuations in these parameters since there is barely any livestock but strangely, my alkalinity drops every day. The first time I tested, it was 5.5 (!) and after bringing it up to 8.5 or so, rapidly drops about 2 points every day. Basically, I am having to dose my alk daily and I don't have anything in the tank yet!

Any ideas? I have heard chemipure can drop dKh but this much?

Thanks in advance

 

[reefndude]

What is calcium and mag at? I could be wrong here but higher calcium levels will knock alk down. I've been having same issue in my tank.

 

[Randy Holmes-Farley Verified Community Expert]

Cycling and rising nitrate deplete alkalinity. Maybe that is the cause.

GFO (like in the Chemipure Elite) can cause nearby precipitation of calcium carbonate, and such issues get magnified in a really low water volume, but 2 dKH per day seems like a lot to me too.

In any case, if you have confidence in the kit, just dose to maintain. I can't see anything you'd want to change to reduce the demand.

 

[bwrag]

I would not use the chemipure your changing 33% of the volume a week that would seem to be more than efficient to me.

 

[reefer_madness_01]

Removed chemipure last week and still getting big alk swings. Dropped from 8.5 to 5 in 24 hours...ugh

 

[bwrag]

Not sure if it maters but do you have aragonite based sand. My best guess would be from evaporation and the salinity difference is throwing off ur test kit. I could be way off though

 

[bwrag]

Aslong as everything is looking good then I would worry to much 5 seems unrealistic to me

 

[reefer_madness_01]

Nothing is looking good

 

[reefer_madness_01]

Salinity is stable, and I have ATO for evaporation. I'll have to check on the sand when I get home. Does aragonite suck up alk? I was thinking of removing it to see if that helps

 

[Randy Holmes-Farley Verified Community Expert]

Removed chemipure last week and still getting big alk swings. Dropped from 8.5 to 5 in 24 hours...ugh

You might need to go with some frequent dosing.

 

[Randy Holmes-Farley Verified Community Expert]

The sand should not be an issue either way.

 

[reefer_madness_01]

Not sure if it maters but do you have aragonite based sand. My best guess would be from evaporation and the salinity difference is throwing off ur test kit. I could be way off though

It is aragonite based sand. Is that a problem?

 

[Randy Holmes-Farley Verified Community Expert]

It is aragonite based sand. Is that a problem?

It shouldn't be an issue unless it is getting solidified with precipitation of calcium carbonate. How high are you trying to keep alkalinity and calcium?

 

[reefer_madness_01]

Its not getting solidified as far as I can tell. It is very fine sand like beach sand. I just tested it again and was hoping it would stabilize after almost 100% water change on friday but it is back down to 6 again. I'm about to do another 33% change with vacuum suction of the sand again. I'll test it after water change...

 

[Randy Holmes-Farley Verified Community Expert]

Its not getting solidified as far as I can tell. It is very fine sand like beach sand. I just tested it again and was hoping it would stabilize after almost 100% water change on friday but it is back down to 6 again. I'm about to do another 33% change with vacuum suction of the sand again. I'll test it after water change...

Water changes generally aren't the best solution to calcium and alkalinity problems.

 

[brandon429]

a help to stop the frustration

you have the option to not only stop testing for alk but for everything but temp and salinity.

it is perfectly ok to get ideal params in pico reefs, or, just stop testing for them and change half your water out weekly for years w good feeding, that works in all 3 gal reefs using any typical brand of changewater, per 10 yrs threads

the corals we keep in 3 gals unless highly specialized are documented to do just fine in the variations presented by each known saltwater brand...im not claiming they are all the same. just that any brand you add to my tank right now with a 100% no partial water change will not impact my system either way, nor any param difference we could measure by changing brands, and thats quite a range per triton tests compiling for all known brands.

if someone has an uber sensitive animal beyond norm, thats a good reason to chase exacting numbers. take linkia for ex, tough in pico reefs due to salinity sweeps we typically get, thats an exacting species.

a hammer coral w do just fine in anything from IO to Tropica marin regarding pico reefs, we enact this principle daily to make long term pico reefs and then make threads on them to document