GFO caked in calcium buildup!

[wakerider017]

Ca & Alk levels are pretty normal. A little low if anything.

I am however dosing 450ml of ALK (just baking soda mixed with rodi) a night over a 9 hour period

& dosing 200ml of Ca (Brs Ca) a day over an 8 hour period.

Seems like a lot! System is ~300G TWV




Past two months GFO has been coated in calcium after only a week or two in my BRS canister.

Carbon seems fine. No build up at all in that canister.


Any ideas or thoughts guys?

[Pittsburgh]

Mg too low?

and why different dosing for Ca and Alk? Shouldn't they be equal?

Sounds like something's out of sync.

[bertoni]

If you dose the alkalinity supplement or even the calcium close to the GFO input, that might be an issue. The more diluted the supplements are before they hit the reactor, the better. How long was that GFO in the tank before the picture was taken?

That dose comes to about 1 dKH consumption per day, which is okay. Many tanks consume 2-3 dKH per day, just due to coralline algae.

[wakerider017]

I'm going to recheck Mg, Ca, and Alk today and report back.

GFO intake is actually pretty far away from ALK/Ca drip.

I dose 2-part into a 40 breeder which dumps into a filter sock and then into a 100 gallon sump, which in-turn has an intake near the bottom of the tank. From here the water goes to an Iwaki 100, which pushes it to a manifold with gate valves. Most of the water is directed back at the tank, but some goes to GFO, Carbon, UV and then whatever is left over gets circulated in the 100 gallon Rubbermaid sump.

That GFO pictured is 31 days old, but it started looking bad at the 2 week mark. I'm betting once it starts getting coated it loses most if not all its functionality.

Bertoni, how do you feel about my ALK being more than double the amount of my Ca? Do you see a problem with that?

[Pittsburgh]

I've had this problem with my biopellets reactor very recently actually... I let Mg get too low while dosing Ca/Alk aggressively. The reactor stopped overnight (or two) with all pellets stuck together with Ca buildup... Topped off Mg to the required level, broke up pellets and all has been running fine for a while now.

[wakerider017]

8.6dKH 360Ca 1200mg

I'm going to have to raise Ca dosing. Everything else looks pretty good.

Mg might be a tad low, but that can be fixed with a water change.

[bertoni]

I think those numbers are okay, and the ratio of calcium to alkalinity is not important. Raising the calcium is a reasonable idea, though.

I might try soaking a clump of the encrusted GFO in a bit of vinegar, to make sure that the crust is calcium carbonate. I'm not sure why precipitation should start so suddenly.

[wakerider017]

Only changes made corresponding to the time frame in which precipitation occurred was the addition of 100lbs Marco dry rock, slight increase in dosing, and the removal of all fish.

Ill soak in vinegar next time to see if it bubbles.