What's up with my tank?

[tacks]

125g FOWLR set up for about 7 months now. Tank is built in wall in basement so it doesn't get much natural sunlight. Wet/Dry filter (with chemi-pure) Berlin Turbo protein skimmer. 100 lbs of live rock, 160 lbs of live sand. Water change of 30 gallons every three weeks. Lighting is VHO. IceCap 660 runs 1-110watt Super Actinic, 1-110watt white actinic, 2-95watt white actinic. The other IceCap 430 runs 2-95watt super actinic. I've cut back on lighting now to 4 1/2 hours per day. Tank is stocked with the following, 3 yellow tangs, 1 flame angel, 1 fridmani, 4 green chromis, 1 lawnmower blenny. Assorted crabs and snails from original cleanup crew. I feed once per day frozen and seaweed selects for grazing. Every third day, the tank does not get fed. Levels are as follows as of today...
PH - 8.0
Ammonia - 0
Nitrite - 0
Nitrate - <10
Salinity - 1.022 (not with refractometer... will get one soon)
Alkalinity - 9.8 dKh
Calcium - 315mg/L
Phosphate - 0.4mg/L
No matter what I do, I can't get rid of this cynobacteria. It's on the sandbed and some rock. I've increased the flow (now up to 7 powerheads), started rinsing/straining food, cut back on lighting, bought chemi-pure. I'm religious with water changes and clean the overflow filter daily. I use Hi-S RO/DI for makeup water and water changes. Fish look GREAT and are very healthy. The tank however doesn't look so good. There is also a film on the surface of the water. I'd rather not correct this problem with chemicals but I'm getting close. Any suggestions? I hope I didn't leave any info out.

 

[flricordia]

I don't know if this has anything to do with what has been causing the diatoms in your tank but I was going to post this account the other day but didn't get around to it.
I have always used -- salt mix in my reef tanks from day one back in the early 90s. On occasion I have used IO and jsut a few months ago I came upon a large bucket for next o nothing and thought I would use it and save on -- cost for a little while.
Well, after about 3-4 weeks of using the IO I started getting diatoms on the glass like crazy. About 2 weeks ago I went back to using -- and the diatoms are clearing up with most of the glass staying clean again. In the past I noticed the same thing when using IO, but thought it might be coincedence.
Anyway, just something I was going to post but didn't yet.
Maybe nothing to do with your tank, just what has gone on with my reefs when I use IO. BTW, I have also see these same results in a friends 75gl when she started buying the cheaper IO. After about 6 months of fighting algae she went back to using -- and the tank pretty much ecleared up after a couple months.
Maybe jsut coincidence with my tanks and hers and IO verse --.
Hope you get an answer, it can be frustrating I know.

 

[tacks]

Forgive me for asking but by -- do you mean reef crystals? I use reef crystals by instant ocean.

 

[nycbob]

what is the phosphate level at? how much of a cleanup crew u hv? i know hermits eat cyano algae, bc i hv seen it in action. it could be old bulbs also.

 

[tacks]

New bulbs as of 11/12/07 so 6 months... Phosphate is 0.4mg/L Also, temp is 77. I think lights should be good for about 12 months with the icecap ballast.

 

[flricordia]

Originally Posted by Tacks
http:///forum/post/2586596
Forgive me for asking but by -- do you mean reef crystals? I use reef crystals by instant ocean.
Well, like I said, that was causing my problem but since you are already using Test kits test either total or inorganic phosphates. Might have organic that is feeding or maybe silicates. Where did your sand come from?
Forget that. I jsut reread your post. Looks like a recycle. Maybe adding too much at one time and wasn';t cycled out to start with.
Nitrate 10 seems high
Over population and/or feeding.
You also need to get some surface skimming in there.

 

[tacks]

Sand was bought online (Caribbean Live Sand). Nitrates are not 10, they are less than 10.

 

[snakeblitz33]

What is your internal flow rate now? You might want to take out the powerheads and try to get only one large powerhead.
Berlin protein skimmers are crap. lol. Get a very large protein skimmer for your tank, something like a Euroreef protein skimmer.
I am also having a problem with a tank of mine, it has a crushed coral bottom, 3 fish, about 55lbs of live rock. I haven't done a water change in awhile, but it seems like a loosing battle.
If I were you, I would try to siphon out as much cyano as possible and do a 50% water change once a week. Try to get some tropic marin salt, I've always had good experience with them.
If mixing up that amount of water is a lot for you, you could get an unused Brute trash can, (around 44 gallons) and fill it with RO water. Make sure you get a refractometer and match your salinity exactly before you to such a large water change.

 

[snakeblitz33]

You are going to have more nitrates in your tank then what your reading on your test kit because the cyano will suck it up.