Aquarium cleaning

[altivo]

Whoa. I had no idea. Y'know, I've had fish tanks for a long time now. Something like half a century or so in fact. Tried marine environment once, but that is just too messy. Generally fresh water, easy stuff like live bearers, danios, and such. In the last 20 years I've finally begun to be aware of the complexity of water chemistry and how delicate the balance is. The idea that it could be actually controlled and corrected when it starts to tilt would have been incredible to me before that.

Anyway, we have one tank that has been going continuously for eight years. Not that it hasn't gone "sour" a couple of times in that period, because it has. But we'd just replace the water, clean out the filters, and bring it back to life. Then just recently we discovered that nothing we could do would bring the pH in that tank up to neutral. It stayed acidic, and would go all the way down to 6.0 in a week or so if left alone.

After seeking advice in multiple places we concluded that it was the undergravel filter, which had been running all those years. In theory, the power heads lift the gunk back up from under the gravel to where the filters and water changes can take care of it, but apparently they don't work that well and over time the space under the filter panels gets very foul indeed. This was the problem.

Today's advice is to remove the UGF completely, or else reverse the flow so that water is pushed down the tubes and under the gravel, forcing the gunk up through the substrate where it can be removed. So we decided to check it out. Moved the fish (seven swordtails of varying ages, and two plecostomi, one about eight inches long and the other quite tiny) into a couple of buckets filled with water from the tank. Took all the plants and rocks out, pushed the gravel to one side and started lifting out the plastic perforated panels of the undergravel filter. I have never seen such filthy water outside the foulest swamp. Black as pitch, filled with sediment, and even smelly. That was surely the problem.

Removed all the water down to the gravel and bare bottom. Replaced it with softened well water (not ideal, but the best we had on hand) and then added some pHDown to start pushing it down toward neutral as our well water is around 7.8 once it goes through the softener. It's also too soft, so I added "aquarium salt" to help compensate. The tank is now cycling through a clean filter element to remove the sediment that remains. Meanwhile, the fish are being slowly acclimatized to a higher pH by replacing a pint of water from each bucket with the softened well water every couple of hours. By tomorrow night I hope the conditions of the buckets and the newly-refurbished tank will match closely enough to allow us to return the fish to the tank.

Comments

[hrrunka]

It all sounds very complicated. Nearest I've ever got to trying to keep fish has been my garden pont, which isn't big enough to look after itself, and tends to accumulate a layer of horribly stinky mud over a year or three...

[altivo]

Same kind of issue. If you have a tiny garden pond, you need filtration equipment and regular cleaning just like an indoor aquarium.

[hrrunka]

This one's about 7ft by 5ft by 18 inches (to 2 feet) and was put in by the previous owners mainly as a bed for aquatic plants. You can see it in the bottom right corner of the icon... ;)

[altivo]

We have a friend with a pond about that size, though it has a small area that is deeper. She keeps a skimmer and a filter pump running during the months when the temperature is above freezing. It started as a pond for water lilies, and she has some very nice specimens. But then she got into koi and there are a lot of large ones in there, more than I would expect the space to permit but they seem to be just fine with it. She used to move the fish to indoor tubs in the winter, and the plants are in pots so they can also be removed when necessary. Now I think she leaves the fish in and lets it freeze over, without any particular problems. Our winters haven't been so cold in recent years, though. Warmer temperatures and more snow and rain than we used to get.

[hrrunka]

Ah, koi are usually quite fussy about water conditions. Next door used to have a pond for koi. It was about six feet deep. They sold the koi and filled the pond in about the time their daughter had triplets...

[altivo]

LOL! So if the kids didn't drown, the koi might have eaten them anyway. I see the logic, sort of.

[murakozi.livejournal.com]

Undergravel filters are a lot less popular nowadays just because of the maintenance issues like you encountered.

A strong enough siphon/gravel vacuum should be able to pull much of the crud out from under the panels. Unfortunately, that also risks getting rid of the bacteria living in the gravel and can screw up the nitrogen cycle.

As it is, you're probably gonna have a mini cycle going on in there once the fish are back in. You might lose a swordtail or two to that. Plecos are such tough buggers that they'll probably handle it okay.

I'd suggest switching to a HoB filter. They're easier to maintain and a rather effective. I prefer the Aquaclear ones to most others since you can just rinse the junk out of the sponge media in them instead of replacing a cartridge. That keeps the maintenance costs near zero. Running both the UGF and a HoB for 5 or 6 weeks should let the beneficial bacteria set up shop in the HoB, then you could remove the UGF altogether.

On my tanks, I have canister filters along with an HoB as 'backup.' Aside from the benefits of extra filtration, I tend to feel a bit safer in case something happens to one or the other. The tank can continue just fine without having to go through a minicycle if one of them goes kaput for some reason or if I get a little overzealous when rinsing their media.

[altivo]

I think we used to normally expect to completely empty and restart a tank every year or two. That prevented this sort of issue with the UGF. Now we expect a tank to really balance and go for years.

The tank is 30 gal. and has a 30 gal. HoB wheel filter with the drop in cartridges. The UGF was supplemental, and I'm thinking of keeping the power head and attaching it to one of those sponge filters that the bacteria can also colonize. The pea gravel in the tank is probably well populated with beneficial bacteria already, and I imagine the plastic artifical plants are as well. We kept both wet and though we disturbed the gravel we tried not to really scrub it around.

Haven't had an ammonia/nitrogen type issue in this tank for many years, so I don't expect this to unbalance it too much. I'm more concerned about the pH change. Sediment has cleared out as of this morning (need to clean the HoB filter, no doubt) but the pH is now over 7.6. Have to get that back down to 7.2 or so in order to put the fish back. I'm tempted to add some white vinegar even.