Water Quality Problems In An Established Tank

[aquila]

Quick background: I have a 180l tank which is home to four very, very large fancy goldfish. The filter is a Fluval 305 - 1000lph or thereabouts. The tank itself has been running in different incarnations for nearly five years now, with constant upgrades along the way, always with the old filters running consecutively or the media transferred where appropriate. The current set up has remained unchanged for about a year.

Over the past four weeks I have been seeing ammonia and nitrite readings, despite vast water changes. Nothing I seem to do will reduce the amount (and yes, I've tried a different test kit, the results are reasonably accurate across different brands!). I've been feeding the fish less, water changing more and more often, but there's still a reading of up to 1.0mg/l of ammonia which is utterly unacceptable. The fish have not seemed affected in the slightest until today, when I caught one of them bottom sitting and I've decided enough is enough.

I have a planned upgrade to a minimum of a 240l tank planned for when we move house next year - this simply can't happen any earlier for logistical reasons. I'm thinking the issue though is not so much the tank size but the filter just being unable to cope with the sheer amount of waste they are producing? Will an additional Fluval 305 make any difference to the situation? What other model of filter would you suggest? In the short term, is the addition of chilled bactinettes going to make any difference while I order in a new filter? What other short term fixes can I use to protect the fish while the new filter matures?

Many thanks in advance from a goldfish keeper whose arms are getting very strong from hauling buckets of water about!

 

[backtotropical]

Hi Aquila,

Sorry to hear you are having problems. The first thing that strikes me from your post is that you say no matter how much water you change you can't get rid of the ammonia / nitrite. Have you tested your tap water? It is possible that your tap water has detectable ammonia / nitrite, and if this is the case, obviously you won't be able to lower the tank level below the tap water level through water changes.

I would say that your tank is probably not big enough to adequately house 4 fully grown fancy goldfish, so an upgrade in size is a good idea. Go as big as you can.

With regard to the ammonia and nitrite problem, I agree that the size of the tank isn't the problem there and the problem is probably the filtration. As you seem to be aware goldfish are very messy and require very efficient filtrtation. If the ammonia and nitrite aren't coming from the tap water supply, i would suggest that the filtration needs upgraded. Another 305 would probably be ideal, or a 405 if you can stretch to the extra cost. Eheim filters are also very good and worth looking into. TetraTec also get a good write up and are cheaper than Fluval and Eheim.

The only problem with adding an extra filter like that is that fancy goldfish aren't strong swimmers and will soon tire in strong current. Maybe you could diffuse the outflow by using spray bars?

If you do get another external, the best way to colonise the new filter is to take half the media from the established filter and swap it for half of the new media in the new filter. That will ensure that the new filter is well seeded and the bacteria growth is as quick as possible.

In the meantime, Bactinnettes could help, as will large water changes (again assuming your water supply isn't to blame). You could also try Ammo-Lock which converts the ammonia into relatively harmless ammonium. Note that this transformation won't affect the result from your test kit, but it does make the ammonia less toxic.

Hope that helps and good luck.

BTT

 

[aquila]

Thanks for the reply BTT

There's no discernable readings from the tap water thank goodness. When I say that the levels of ammonia and nitrite won't decrease with water changes, what I mean is that immediately after a water change there is a drop in the levels, but it's way back up there within as little as 24 hours.

I've budgeted for a new 240l next summer which will happily coincide with a house move, but until then I literally don't have room for a bigger tank - the buggers already take up most of the living room, lol. I'm something of a goldfish activist with regards to bowls and small tanks etc. but even I thought a 180l would be an adequate mid-term home. I am shocked at their rate of growth, it's phenomenal. To think that they started out in a 10 gallon growing out tank!

I'm something of a Fluval fan having found the 305 so easy to use after previously having had internal filters, but I will certainly look into the other comparable models. I know my uncle always swore by Eheim when he had fish and wouldn't use anything else - definitely worth checking out.

Current is not an issue with these guys - they're big, clenched-fist-size big, and strong if slightly uncoordinated swimmers. Extra oxygenation from a good outlet is always a bonus anyway.

I'm thinking that the advantage of having another Fluval will be the ease in swapping media to colonise the new filter - the 305 and 405 use the same sized media and have four sponges each alone so I could effectively be running two well-seeded filters from day one.

Ordering a new filter it is - so close to christmas it's giving my credit card a bashing, but you have to be a little bit mad to have goldfish I think.

Many thanks again BTT for reassuring me I'm going in the right direction.

 

[rabbut]

More filteration is your long-term fix, as BTT says Personally, having used 4 different brands (Eheim, Tetratec, Fluval and Rena) I wouldn't use a Fluval on a home system even if you paid me... Compaired to internals they are a dream, but compaired to other externals, they are a royal PITA. I personally only use Tetratec now, but any Eheim other than the Eccos (that I ran) and the Thermos are suppoed to be very good. Pro 2's are the range to look at if you are buying an Eheim Rena are good if you are happy to keep spare seal rings about, as they can leak regularly IME. They only do it after maintanance like, so it's not too big an issue if you have cash to throw at parts...

Short-term, Ammolock as BTT says will de-toxify the ammonia. Salt is good for de-toxifying nitrite though Use it a 1/10th of the marine dose (3ppt) and you are laughing, if coupling both with regular large waterchanges It works out about 1 level tea spoon per gallon

All the best
Rabbut

 

[Syphoniera]

rabbut had a brilliant suggestion - I'm just not sure if the recommendation given for 1 spoon of salt per gallon was a typo, as I've heard 1 spoon per 20 gallons for reduction of nitrite uptake in fish suggested as being a level which will not harm plants or freshwater fish even over the long term.
Aparently even smaller amounts are useful.

http/www.algone.com/salt_in_fresh.php

... Salt can be used to prevent nitrite poisoning, if the chloride ions are 30 times the concentration of nitrite ions.

Nitrite reaches a toxic level at about 0.1 ppm, which would require about 3 ppm of chloride ions. Depending on the salt (sodium chloride) used, it might translate to about 5 ppm (given that common salt has a chloride concentration of 60%) to ease possible nitrite poisoning. This in mind, one teaspoon of salt would be sufficient to provide this effect for a 300 Gallon tank.

As a brief summary, 1 teaspoon per 300 Gallons will do as described above. Table salt does contain iodine and anti caking additives (to prevent the salt from clumping together). Iodine is essential for certain plants and animals, and definitely of no concern, considering the low amount of salt and the low concentration of iodine added to the salt. Iodine at this concentration should be rather beneficial instead. ...

... Salt does interfere with the osmotic regulation of fish and plants. It should be left alone; nature regulated that part itself, by creating freshwater, brackish and saltwater fish. ...