Recurring Bacterial Bloom

[Tolak]

There is a 72 gallon bowfront in the shop where I work, with a reccuring bacterial bloom. Some info;

Ammo 0
Nitrites 0
Nitrates 20
pH 7.6
gh 179
kh 90
Temp 80F

Same water as I have at home with my tanks, using Prime to dechlor.

Inhabitants are a 14" common plec, 2 5" iridescent sharks, ( I told him they get as big as the bumper of his truck) 2 rosy barbs, and a clown loach ( I told him he should have a few more than one, but why listen to me).

The tank was moved from his house to the shop around 4 months ago. He has had it running for years, kept the filter media & gravel wet during the move, the move & setup went without too much problem. It's located in the office, no fumes or chemicals from the shop get back there.

All fish are healthy, but the water looks horrible. He was running a magnum 350 pro for years, the gaskets gave out one day & started leaking, around 6 weeks ago. Took him 2 days to pick up a Penguin 350, & didn't save any of the old Magnum media. Of course the tank cycled, went through a bacterial bloom, then cleared up after 2 weeks. I think the only thing that saved the fish was a deep bed of mature gravel.

A few days after it cleared up, it went cloudy again. Some water changes helped, he also added a new Magnum 350 at this point. I told him don't touch, or even look at any filter media for a month, it needs to get a good bacteria base, no matter how filthy you think it is. It cleared up after a week, then bacterial bloom again, after a few days of being clear. Cleared up again. After it stayed clear for nearly a week, it started to get cloudy again early last week.

I stuck around after work today (this guy is the owner's son, I was on the clock, overtime is nice!) to take a look at how he was doing tank maintainance. 25% water change with a little gravel vaccing, adding water with a clean container that he hides under the tank, adding dechlor as he fills. Nothing out of the ordinary as far as I could see.

One odd thing is a buildup of some sort of semi-opaque slime around the tank. I've never seen this on any of my tanks, only buildup I get is lime thanks to the hard water. He is running the standard cartriges in the hob, regular filters in the Magnum, with Black Diamond carbon. The only thing, other than me changing double or triple the water weekly in my tanks, is the carbon, which I don't run on any regular basis.

My next step is bringing in some of my hoses & pumps, forget about buckets, & doing daily water changes. Unless anyone has any idea what may be causing this bacterial bloom, or the slime buildup. Water changes are the best remedy I can think of.

Thanks in advance!

Tolak

 

[Mr Miagi]

How much natural light is hitting the tank? Could it be an algae bloom rather than bacterial?

Also, how much does the bloke feed them?

 

[CFC]

It sounds like the filter isnt big enough to cope with the bioload.

Let me see if i have this right.
The water turns cloudy from the bacterial bloom so you stop feeding and do a few water changes, after a few days the water returns to normal so you resume feeding again and within a short while the water clouds up again?
If this is the case its because the ammount of waste created by the fish requires more bacteria to cope with it than the media in the filter can physically hold, when the bacteria mulitiply quickly to cope with the excess of waste they have no where to go and spill out into the tank. The obvious solution would be to add another filter or change the one on there for one with a larger media capacity.

 

[Tolak]

It is a bacterial bloom, a beautiful milky white. We tried leaving the light off, as well as covering any openings that let light in the top with opaque plastic.

CFC, that could be the problem, spilling bacteria ito the tank from what I would consider not quite mature filters. The hob is rated at 330 gph, the canister 350 gph. That gives 680 gph from decent but not what I would consider ideal filters, which I always divide by 2 because filters slow down when really mature. This gives 340 gph in real life, which is turning over the tank around 4 1/2 times per hour. Personally I would like to see more, but I am an overfiltration freak.

You both have hit on something, the feeding. These are decent size fish, they could be fed every third day and get by just fine for a while. This would give the filter media a chance to catch up with the bioload. It may also address the slime issue, something I have not seen before.

I'll try telling him to feed every third day for a couple of weeks, then every other day for a couple more weeks, see if it does anything. If it's not looking better after a couple weeks, I'll bring in some gear to do daily water changes, or perhaps pull a spare cycled filter off of one of my tanks to try to give it a jump start.

Thanks for the help!

Tolak