algae eaters in a Koi tank

[daniel]

Hi Everyone,
I am curious as to what y'all would suggest to help "clean up" a cool (not tropical) water koi tank. I am getting thick bright green algae on the rocks and some on the glass. The tank is 6'x2'x1.5' and I guess about 180gal volume. The fish load is WAAAAY to high with about 12 koi ranging from about 6" to 12" (average TL~8") Like I said, WAAAAAY overstocked IMO.
Worse, I just do the maintenence, and am not in control of feeding, so I know (despite much pleading/protesting, etc.) they are being overfed to boot!
Some other tank specs:
2 corner overflows--> a DIY sump-wet/dry; don't know the turnover rate right now
UV sterilizer (Watts??)
2 36W full spectrum flurescent lights w/ reflector; 12on/12off
plastic plants, but would definitely consider "koi-proof" plants

Predictably the algae is fastest growing under the lights (both tubes are centered in middle of tank)
Despite my warnings, several plecos were added (in a series) but failed to survive more than a week or so )-: -I'm guessing because of low temp related stress. (Tank is not heated and is generally in the high 60's to low 70's)

Several largish (~2") "pond" snails also turned up dead )-:

Other attempts include trying to establish "Malaysian Livebearers" as well as "common (small) pond snails but w/out much success.

So for now I will continue to lobby for decreased feedings (maybe every other day!). The photo-period is more or less set though...
Oh and I perform 25-30% WC about every 3-4 weeks, but am considering increasing the frequency to ~2 weeks. bleh!

Thanks in advance,
-Daniel

[icebear]

i'm sure the nutrient/chemical concentrations in the water are way too high for anything living to be added to that foul sounding soup.

i think maybe the Koi have somehow managed to adjust to the poor water quality over time but the newly introduced creatures simply can't handle the shock.

there is nothing that can be done other than a serious overhaul of the husbandry techniques being performed on this tank. Adding something to eat the algae is not going to fix it, all that animal will do is clean off a place for more algae to grow and create waste while doing it- which in turn will create even more nutrients for algae to continue to take over.


What is the situation where you do the maintenance but have no controll over feeding and stocking?

Serious regular waterchanges and removal of all decaying matter might do some good but it will be a losing battle if the plan is to keep this tank overstocked.

it is unfair to the inhabitants at the very least. Koi need more room than this.

Do you test your water for nutrients at all? Phosphates, nitrates, nitrites, ammonia etc?

trites, and ammonia need to be ZERO at all times

nitrates (to an extent) and phosphates are not too horrible but a high level encourages algae to grow......

[Stang69]

Yes you are right on the oversotck bit. I would actually be doin weekly water changes and put the food in ziplocks and tell them this is how much to feed each day and take the rest with you.

You mentioned the algae groes under the lights. You may wanna change the bulbs and put them on timers that may elp somewhat also.

Regulate the feedings and regular water changes and aquarium salt. (not that the salt will decrease the algae but.....) May wanna look into a UV also this may help to a point too



HTH

Jeff

[Deborah]

More water changes are about the only thing that might help. But experts recommend ponds of 500-1000 GALLONS as a minimum for koi. In the long run I don't think a 180 gallon tank is going to cut it.