[N9CQB]

I am having trouble with zoos or small polyps vanishing over a period of several months. They just stop opening up & shrink one by one over time.
Tank is 90 gal reef w approx 50 # LR, 1 yellow Tang, 1 Cream Angel, 4 Damsels, 2 Clowns, 2 Chromas, 1 Red Flame Angel, 3 cleaner shrimp, 2 sand sifting stars & several types of snails (10-15).
Sump is ProClear w Bio Balls & Protein Skimmer. Tank has an overflow.
H20 parameters are:
Ca 380 (can't get it higher for some reason)
DkH 8 Nitrite 0
Ph 8.2 Nitrate 20-25
Phos 0
Ammo 0
I use only RO water with Instant Ocean salt. Salinity is 1.022
Lighting is 4 x 65 w Compacts + 80 w flourescents in another fixture & zoos have been in low to mid area of tank.
Thanks !!

[rlcline76]

Here is the thing about zoas. Water quality, light an flow will dictate health.
You need to work on your parameters. Both KH and Ca are low enough that you could try using a 2 part solution like Kents Tech cb.
Get some water changes going and ditch those bioballs if you want lower nitrates and up that salinity.
Try moving the zoas to a better lit area of the tank with good flow. If you notice any cheesy like appearance on the polyps that would suggest disease, not just an environmental problem, I have read that you will want to remove those from your tank completely.

[N9CQB]

rlcline,
Thanks. I have been using Kent Tech CB, but it hasn't raised the CA & DkH much. i use it about 3 x week.
Get rid of bio balls?? What would you replace them with ?

[rlcline76]

Lots of people are using live rock.

[e_baer]

Live rock rubble*

If you cant get the CA raised try to raise the DKH up to 10 or 11.

Also, are you using any type of buffer?

[N9CQB]

Thanks. I'll give the LR rubble a shot when I have the $$ to buy some. Today I cleaned the sump & bio balls. The polishing block was very dirty. I build a denitrator 3 weeks ago. Think I'm slowly seeing a reduction. The only buffer I'm using the the Kent CB part A & B

[e_baer]

Buy LR rubble!!! you can make it yourself! Just get a hammer and a LR chunk. Then start smashing and you will have some LR rubble.

[N9CQB]

Thanks for the info...Guess i wasn't thinking !!!
By the way, why does LR not produce nitrate the way that Bio Balls do ?? There is still aerobic bacteria in the LR