Ammonia spike

How long does the ammonia spike in a new tank last for? I think mine is at that stage now so I've done a 50% water change. Should I do one every day?

Your question lacks the specifics (tank size, number & size of fish etc) with which to formulate an answer. Basically if you can measure ammonia, then there is enough to feed and grow the correct bacteria, so now you need to keep the levels low enough to prevent harming the fish (unless you are doing a fishless cycle, in which case you would leave it all alone). The rate at which you will be doing water changes will depend on many variables, ...anywhere from several times a day to every 2-3 days. Bio-Spira and/or aged filter media will speed the process up. hth

Tank is 50 gals, set up 5 weeks ago, a dozen neons, 4 platties and 3 catfish added a week later. PH is 6.2 (can't seem to get it any higher than that), Ammonia is low but just showing. I also have a well cycled 40 gal cold water tank that holds 4 fancy goldfish. would it help if I moved the filter from there to the new tank for about 3 hours? Or would that not be enough to make a difference. Obviously don't want to remove the filter for any longer than that for the goldies sake. And would that harm the goldies anyway, putting it back in the tank? Can bio - spira be bought in the UK?

Much better stats, 50g at about 25% capacity at low pH (very important as ammonia at 6.2pH is actually ammonium ions, NH4 which is non-toxic). Under these circumstances, I would not worry too much. Take a bit of dirty filter media from your Goldie tank and put it into the 50g's filter. Your problem will probably be the nitrites (NO2) which is what the NH4 will be changed into, so the more bacteria you can add now (dirty filter media), the less NO2 will hit the water (it will be converted to nitrates (NO3) which is also relatively non-toxic at low levels (ain't chemistry fun?). Let us know what the NH4 and the NO2 levels are though. This is what will indicate whether water changes are needed, though you can do water changes anyways, just don't do huge amounts. hth

re: Bio-spira in UK, don't know and you probably don't need it if you keep monitoring the situation and don't overfeed.

Put a couple of marble chips or a few pieces of sea shells in your filter. That will slowly raise your kH which will help to keep your pH stable, and raise it a bit. I suspect the waters buffering capacity is used up, or almost used up and your kH is well below 4.5dH.

A lot of water for the few fish you have in it. As for as the cycle, it doesn't start untill there is ammonia in the tank (uneaten food and fish), so the tank is only 4 weeks old with a light bio-load. pH 6.2 - like NetMax said, the ammonia is non-toxic ammonium so your test kit may give you false readings as the ammonium level builds up. As the kH/pH raises, the ammonium will convert to its toxic form, ammonia. By adding 1/3rd of the media from your goldfish filter to your new filter, you shouldn't even have an ammonia/nitrite spike - your filter, with such a light bio-load will be pre-cycled.

? - not needed if you do the above.......... Frank

The goldfish filter is a totally different filter. - Fluval, whilst the tropical filter is a juwel otherwise I would just have swapped one of the sponges from the goldie filter. I rinsed the top juwel sponge with the fluval sponges when I last did a goldie water change - should I do it again? The juwel filter has a nitrate filter and a carbon filter. Perhaps I should rinse these with the goldie filters? Should I add another couple of fish?

That would have been enough to seed your filter - by adding established media from the goldies filter, I was trying to get around the cycle, but that isn't going to happen.

I don't beleave that will help speed up the cycle. By now, every thing in the tropical tanks filter will have bio-film.

I wouldn't do that untill the first cycle is over - 0 ammonia/nitrites readings. Then all you will have is the short mini spikes each time you add (a few) fish.........Frank

OK, NOW I regret taking literature instead of the sciences. Just done another 50% water change, adding tap safe to the tap water. Before the change, the readings were PH 6.4, Ammonia 1.0ppm, Nitrite 0.25ppm, Nitrate 20.0ppm After the change they are PH 6.4, Ammonia .50, Nitrite 0, Nitrate 5.0 ppm. Tank is at 78o, substrate is sand, planted with 3 or four live plants, piece of lava rock, piece of coral taken from goldie tank, some plastic plants. My goldies tank has ph of 7.2 despite doing water changes at same time as tropical and using exactly the same water with same treatment. would it be an idea next time to mix the water?

It's not clear how this tank's pH is 6.4 after only 5 weeks, while an older established tank with Goldies is at 7.2, however having low pH works to your advantage at the moment. However I do agree that bringing your kH (buffer) up would be a good idea, but as this will make your pH rise and ammonia toxic, I think you should wait until the tank is cycled. Frank had a good idea of adding some marble chips, as this would increase the kH very slowly (keep your pH from crashing). Regarding incompatible filter media, take the Fluval sponge pre-filter out and give it a squeeze into the new tank's filter or near the intake.

In any case, your numbers are much better, but I would do smaller water changes than 50% to not shock them, and don't let the Nitrite get too high.. Also I don't trust the accuracy of water tests which are done immediately after a water change. I usually wait about an hour before checking the water again. I don't know why this happens and I might be