General Advice: Tank Equipment and Cyano

[M@]

Hey, first post, but I've been reading for a few years on and off.

I have already setup everything and it has been operational for 9 months. Since this site is so informational I didn't even create a username until today as a last resort. So thanks for a great forum.

My tank seems healthy, but... I want to kill off the dominant form of life in it; Cyanobacteria. First I want to make sure my equipment is not part of the problem. This way after I do several blackouts(more on this later) I won't need to do it again.

Tank:
90 gal.
2 Emperor 400's with all of the slots used for media and flos-filters, and the flow all the way up.
2 40w flourscents (Phillips: Natural Sunshine, and Plant & Aquarium) 12 on 12 off
Compact flourscent (2x65w 50/50 from my salt water days) comes on for only the middle 8 hours of the day
I have pea gravel mixed with flourite and a small layer of river gravel on top to keep my African out of the plants
I have a few pieces of drift wood and a few large pieces limestone that haven't begun to brake down.

Any advice filter material, and blub selection would be appreciated.
As you can see from some of the things in the tank now, I didn't always check with AA before I put it in use.

Livestock:
5" Ocsar Well feed
3" African

3 broad leafed plants 2 x 5" diameter 1 x 3" diameter
2 thin/long leafed plants 10" long
I haven't checked nitrate or any thing else in the tank. This will happen tomorrow hopefully.

Up to now I have tried adding the compact flourscent, and then cutting back the timers on both 3 hours. I tried some phosphate absorbing crap that worked well on my salt tank. So far nothing. I gave up just to see if somehow it would just burn itself out. Now there is cyano covering everything. Its so thick on spots that O2 bubbles form under the surface and peal away the crust in ruptures. Flow dosen't seem to have any effect as there is cyano on everything, though the emperors don't put out a direct stream.

My biggest concern at this point in the development of things, is that the cyano is so developed that it forms the major part of my bio-filter, and that removing it will wreak havoc. Is this a valid concern? If so what do you recommend?

Thanks and all advice including the obligatory comments about how I dropped the ball are all welcomed.
Matt

[Devilishturtles]

Hi Matt, welcome to (being a member of) AA

You have valid concerns with the cyano using up your Nitrates and stuff, but if you think about the other side of that, that is likely your issue here.

How often do you feed your 2 fish, what do you feed them, and how often do you vaccum the gravel and change the water?
When is the last time you changed the filter media? Cleaned it? With oscars especially, extra gravel vaccuming and water changes are usually required to keep the tank water good and algae free.

If you go testing your water now you might find your nitrates low, which is common in a tank full of algae. It would still be beneficial to know your other water test readings such as ammonia, nitrite, nitrate, pH and Alkalinity.

About the algae...if it were me I'd spend as many hours as it took to manually remove all the cyano you physically can. Do a really good gravel vaccuming and water change after than, making sure all the algae is gone. Then I would take a dark thick blanket and cover the tank for three days, leaving the lights off and not letting any sunlight in, no feeding the fish, etc. Pop the blanket off, do another water chang, (feed the fish now. ) and see what happens. Try cutting your lighting cycle back a few hours and feeding every other day. If you feed daily, increase your gravel vacs to twice a week.

Hope this helps.

[M@]

pH 7.9
Ammonia about 0
Nitrite 0
Nitrate 0

General Hardness 143 ppm
Carbonate Hardness 125 ppm

edit* CH = Alk doh! /edit*
I didn't have a chance to figure out the formula for alk yet, but I will when I get back tonight.

The filters get cleaned out about once a month and the water gets changed maybe once every two months 30%.

I feed the Oscar only and the african eats the leftovers, but I know he can be messy. I'll lower the feeding for a few weeks, and clean the mats of cyano. At this point I'll consider the blackout. Hopefully this would give the tank a chance to regrow other bacteria. Unfortunaly as soon as I clean the mats they grow back much faster.

[Devilishturtles]

Yeah, your nitrates are just being eaten up by the algae. Doing a water change every two months is likely your problem, if I had to guess. I would consider doing water changes atleast twice a month, but probably more often until you get your algae issue under control. Rinse (don't change, just rinse) your filter cartridges when you do a water change. This will all help limit the nitrate, which the algae is feeding off of. Unless you do that, you'll probably just keep having algae problems, and I know that cyano sucks to look at.

[M@]

I lowered the light time again, and reduced feeding, and have noticed a huge reduction. Plenty has totally died. I feel much better about doing a black out after much of this has already died out. It may not be nessicary in the end.