Green Water
Posted: Wednesday, June 17, 2009
by Nick North
Aquarium Hints and Tips
If you have an aquarium, sooner or later you will experience green water. It nearly always happens just before the in-laws are about to visit or you've invited friends over for dinner. Your fish disappear behind a green haze and you sit there dealing with the jibes and digs with a forced smile on your face. "Nice tank, shame about the fish" "I didn't know that there were green goldfish"
Yes it's annoying, Yes it's ugly but don't get too stressed about it. It isn't harming anything except your pride.
Don't treat the green water, avoid trying for a quick fix, find out what caused it and treat that, then hopefully the green water will stay away.
Green water is an algae bloom of single cell algae and is an indicator that something is wrong with the water chemistry. If you want to get rid of it and stay rid of it you need to test, test and test again until you have determined what is wrong.. It is always worthwhile having a full test kit ready for these occasions.
Algae control is nutrient control.. If you have an algae bloom it can be caused by a number of different factors or a combination of them so you need to find out what the cause is and deal with it. This is what makes green water so frustrating because it could be a single factor or it could be a combination. Remember that when you set up your tank, you set up the perfect conditions for plant growth and algae is a plant. What you need to do is look after your plants and get them to help with the algae so here are some things to try
- Make sure that there isn't too much external light coming into the tank. I once got green water because one end of the tank got direct sunlight for two hours as the sun went round. Three sunny days was all it took.
- Use a phosphate absorbing material in your filter if its available
- Reduce the amount of light, less time or intensity or both.
- Cut down the food and make sure that it's all getting eaten.
- Vacuum the gravel to remove all fish waste.
- Check your fish stock levels. It may be that as fish have grown you have inadvertently overstocked your tank.
- Use a fine filter and do more water changes for a while
- Add fast growing plants which will compete with the algae for nutrients
- Add CO2 which will encourage plant growth stealing food from the algae
- Cut back on fertiliser for a week or two
- Add some floating plants
Controlling green water is about nutrient control, depriving algae of the nutrients that they need to grow so either reduce the nutrients by putting less in or deprive them by encouraging your plants to grow and compete for the nutrients. Look after your plants and most of the time they will deal with the algae.
Finally be patient. If you find what caused it you can hopefully avoid repeating the same mistake. Sometimes green water will simply clear itself leaving you wondering what happened.
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Top-level comments on this article: (3 total)Great article. Well done.I have a different soluion - remove the fish into another container. Add vinigar to the water and leave it for a day or so - Algae hates acids. Then drain the tank and clean it. Before adding the fish check the PH if it is too low add lime untill you get it right about 7-7.5.This is the methord I have heard. Do you think it would work?Please log in to respond to this comment.
This method might work in a fish only tank,(never heard this one before) but would play havoc with a planted tank. If the tank is fish only you can always cover it, blackout, for up to three days. The fish wil sleep a lot but the green water will disappear. A lot less work tooPlease log in to respond to this comment.
Informative article, Nick. Wow- there is a lot more to keeping fish than I imagined. I think I will stick with my dogs! :-)Please log in to respond to this comment.
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