http://forum.aqua-fish.net/ A forum devoted to aquarium fish, plants, techniques and fish keeping as a whole. en http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#1 I just purchased a 6 gallon BioCube tank which has everything in one neatly self-contained unit. I have a couple of plants in the tank to go with 4 gouramis. The question I have is that there are absolutely no bubbles going on in this tank. The water circulates like a vortex, and there is rippling on the surface, but there is no way to get bubbles. The fish seem fine, but how do I know if there is enough oxygen in the water? tagn 2009-06-08 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#2 If the surface water is being agitated then oxygen will be absorbed from the atmosphere. When air bubbles are added to a tank, they do not add the oxygen, its when the bubbles hit the surface that they have the same effect. mickey 2009-06-08 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#3 4 gouramis is quite alot for a small tank. make sure they are dwarf gouramis and make sure you do your weekly water changes to keep the water quality up. good luck weirdartist 2009-06-10 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#4 just to add to that, although its not ideal, gouramis like bettas are labyrinth fish, and as such take in air from the surface as well as from the water, so oxygen levels arent incredibly important. having said that, they do flourish in better conditions. weirdartist 2009-06-10 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#5 I do have dwarf gouramis, who seem to be doing well. During my weekly water changes, how much water should I be taking out? The information I've been getting from the pet shop has ranged from 25% once a month, to 75% every week. Also, should I be switching out the cotton every week? I really appreciate all your help! tagn 2009-07-06 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#6 I would usually suggest about 25% a week, since you have quite a highly stocked tank, it will depend on how the nitrite, nitrate and ammonia levels are. You can get these tested in your local fish shop (usually for a £1 or even free) or buy a test kit (liquid test kits are more accurate than test strips.) If these levels remain within normal, safe perametres (test them once a week until the tank is mature, if you can) then your fish will be fine with the water changes you do. The cotton in your filter should not be removed, apart from rinsing it in the water you take from your aquarium in a water change. By swapping it with a new one, you are removing a large quantity of good bacteria which help to process your tank's waste. You will also be wasting money. By rinsing the filter parts in aquarium water you are removing large particles and retaining bacteria, the used aquarium water wont damage bacterial colonies. Well done for asking questions, sometimes it can be a bit scary not knowing things, and asking questions can be hard, if there were more inquisitive fish keepers like you, there would be much happier fish out there. :) weirdartist 2009-07-06 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#7 I think I have to find another pet store because they don't carry the testing kits. The fish seem like they are doing fine, but I seem to be losing the battle against the diatomic algae (the brown fuzzy stuff I read about on this site). I've been changing out about 50% to 75% of the water and scrubbing most of the stuff off during each water change, but it keeps coming back. Do I just have too many fish, or am I missing out on something with my tank? I even tried changing out the charcoal. Thanks again for your advice. tagn 2009-07-21 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#8 1stly make sure your light is only on 8-10hrs a day. Don't overfeed the fish. I would change about 25% a week, unless the water quality is bad (buy a test kit online, just tap in aquarium test kit on Google shopping or something). Test your tap water, if the nitrates are high in the tap water, the water in your aquarium wont get any less nitrates in a water change. Keep scrubbing the algae off if you can, do it in a bucket of used aquarium water to help the good bacteria survive. Try introducing live plants, just one or 2 could get rid of the algae by out-competing it for nutrients. Good luck! weirdartist 2009-07-21 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#9 you could also buy algae eating species such as cherry shrimps (but tey need a very well kept mature tank, at least 6months) or snails (ram or apple snails are common, however be aware the gouramis love a snail snack) dont buy 'chinese algae eaters' or anythng under a similar name, they will not eat much algae, an will munch on you gouramis (trust me, i was told they would be fine together once!) I personally have to say snails are quite an appealing option, usually cheap, very easy to keep, dont need much fussing, unless you want to fuss over them I have kept rams in my 1st tank since we 1st brought it. you probably dont want to buy any algae eating fish at all, since you tank is already over stocked, and most of them arent what the shop says they are. :) weirdartist 2009-07-22 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#10 Okay, I got my water testing kit, and found that my pH is a little high at 8.0, but everything else seemed good. I guess the Nitrate level will increase as the tank gets more mature. I wish I read your other comment regarding the algae eaters earlier. I purchased two sets of two siamese algae eaters. The last one just died yesterday. For whatever reason, they don't do well in my tank. I'm going to go and look for some cherry shrimp. Would amano shrimp work as well? With regards to the diatomic algae, I think the problem was that I was leaving the light on for most of the day. It really seemed to clear up quite a bit by not leaving the light on. I have also been getting this white stuff that only grows on the caulking of the tank. It comes off pretty easy, but makes the tank look like a giant snow globe. Any thoughts on what this might be? Thanks! tagn 2009-07-31 http://forum.aqua-fish.net/?topic=biocube-tank-oxygen-levels#11 dont buy shrimp for a young tank (under 6months) they probably wont live very long. Your best bet is either ram snails or apple snails, and keep up the scrubbing. do you have a live plant in the tank? Im no expert on the white stuff, i'd recommend asking these guys: http://www.fishtankforum.co.uk im not terribly good at identifying things tbh nitrates should be kept at the right level with regular water changes, keep testing the tank once a week if you can afford to. If you are desperate to get shrimp hold on for a few more months until your tank has matured. at least siamese algae eaters arent aggressive. With an overstocked tank you will want to keep biological load at a minimum, so i would strongly suggest snails rather than fish at this point. The light should usually be on 8-10hrs, depending on the tank species/preferance etc. and never on more than 12hrs. Try to switch it on and off around the same time each day, as this will keep fish stress down. Also make sure you arent over feeding your fish, this is a common cause for algae/bacteria/poor water. for 4 dwarf gouramis I would recommend a small pinch each day, remember fish have much lower metabolisms and dont need as much energy as humans. Also if you have an accidental over feed it is possible to minimuse problems by either netting excess food or using your gravel vacuum to suck peices up, make sure you do this after a couple of minutes to get the best results. I seriously recommend chatting to the fish tank forum guys tho, they know lots more than me and they are all really friendly :) weirdartist 2009-08-01