cyno

[choirboy]

I know everyone says (in general) that cyno is caused by water, light, nitrates and phosphates.

Tank is about 6 mths old. All water parameters are very stable. ph 8.2 - 8.4, temp 77-80, sg 1.024 to 1.026, ammonia 0, calc around 450, alk/kh around 8 - 10. Only use ro/di with tds = 0

for the first 3 mths phosphate was less than .03 and nitrates were 5 - 10. The past 2 months, I have reduced phosphate to 0 and nitrates to <5. I test several times a week.

So

Why can't I get rid of the cyno on the gravel and on the rocks? Had it for almost 2 months. Only have my 250 de halide 14k phoenix on for about 8 .5 hours a day. Bi monthly wc of about 15% each time.

btw, this pic was taken after a 3 day blackout and some cleanup on my part so there isn't much cyno in this pic.

any advice?

 

[ct_vol]

There may be phosphates bound in the rock, leaching back out and causing the cyano. From the pics it doesn't look too bad. You may also consider increasing for within the display tank.

 

[Sn8kbyt]

Had I got the first response looking at the pic you posted i would have said the same about your rocks.

Was it mostly base rock?

 

[Shaummy]

What do you have for flow in your tank? Is the cyano concentrated in one area?

Also, what do you have for a clean up crew, and how much are you feeding?

 

[choirboy]

First, sorry for the pic with no cyno. I just added 2 pics I took tonight below. Cyno still is not too bad but its coming back and will get worse as the days go by I guess.

Second, the rock was dry Pakuni from BRS. I don't know if there is extra phosphate or not in them?

Third, the flow is ok. 2 cheap hydor koralia power heads at about 900 gph on opposite sides of a 58 gal oceanic 36" x 18" x 21". They move the gravel (a little) but the cyno doesn't seem to care. Not much of a clean up crew, 3 nassarius, 3 mexican turbos, 1 fire shrimp, and 3 hermits. But there isn't all that much to clean up I don't think? I don't feed too much. I have 5 yellow tail blue damsels. Maybe the equivalent of 1/2 a frozen cube once a day. All gone in about 2 to 3 min.

 

[pkane11384]

You're rocks are most likely leeching phosphates. I'm not sure where your powerheads are positioned but the spots where your cyano is growing may not be getting the flow the need. I had it on one of my rocks, cleaned it off and then added a Hydor-Flo to the outlet of my return pump and I haven't seen it come back yet. You may also be overfeeding your tank. I've always rinsed frozen cubes when I fed them also

 

[Sn8kbyt]

I used the same rock from BRS and had the same problem. I eventually removed half of it as originally planned and put it in a 29g I was starting up. The problem disappeared in my main tank after a few months and got aggressive in the 29 gallon.

Algae blooms consume phosphate so tests that read 0 after it is established in a tank mean nothing. There is still a source being introduced somewhere. I would limit feedings, cut the light for a few days, and rinse a food you put into the tank. I did that with my main tank and although it took a while I won the battle.

EDIT: I also started running GFO in a canister filter until I got my reactor.

 

[ridetheducati]

Cyano out-competes green algae for P at low N ratios, green algae out-competes cyano for P at high N ratios, and diatoms out-compete green algae for P at high Si ratios.