water conditioner

[esoxlucius]

When evaporation eventually leaves my pump section a bit low in my sump i top up with a few litres of tap water. It's not worth conditioning this small amount so i just add it as it is which led me to my question. What's the maximum percentage of unconditioned tap water you can add to your system before the chlorine becomes an issue?

 

[Betta132]

Chlorine evaporates. It won't stay in your tank long, so it doesn't really have a chance to build up to a noticeable amount.

 

[Drstrangelove]

http://www.academia.edu/4121636/Stu...n_Health_and_Growth_of_Some_Ornamental_Fishes

If you read the above study, you will conclude that water supplies can have residual contents of up to 2.0 mg/L of chlorine and that concentrations as low as 0.1 mg/L can kill shrimp and other aquatic organisms.

This implies that if one adds just 5% of the tank volume as untreated water, that you can have serious issues.

Of course, this is a generalization of the facts. Some fish species can withstand more chlorine, older fish can withstand more chlorine, some water supplies don't have that high a level of chlorine, some water treatment centers vary the amount of chlorine from day to day or season to season, and some fish, while injured don't actually die within a few days of exposure.

At low levels of chlorine exposure, fish may simply eat less, become more susceptible to other diseases, or pass away earlier than they might have, and in those cases, chronic low level chlorine exposure isn't suspected.

So, one can never be certain from one tank to another, even from one day to another what that maximum % will be.

Given the seriously low cost of treating water for chlorine however, imo, it just seems a better investment to treat all the water.

 

[skjl47]

Hello; With the assumption that you have only chlorine in the tap water, a jug of water can be allowed to sit for a few days. I put water into open containers and allow it to sit for around four days. I leave the caps off and stuff a bit of filter floss into the openings. The floss keeps mosquitoes out (or in) if i leave a container around a while.

If you have chloramine this does not work.

 

[duanes]

I agree with DrStrangelove, and the idea the chlorine quickly evaporates is only true if your water supplier uses "free" chlorine. If your supplier uses chloramine, it does "not" evaporate quickly. When I worked for a water supply company we did experiments to see how long our 1.5ppm/L dose remained as residual, and after 2 weeks of sitting, it had barely dropped 0.2ppm.
Most fish diseases are related to stress, which compromises their immune system, so even a tiny amount of chlorine residual can be the difference between a healthy, and a not so healthy tank.