No Free Chlorine

[openbahr]

If your pool is vinyl and has no exposed grout from tile or any other plaster-like surface touching the water, then you don't need to worry about the Calcium Hardness (CH) level; that is, you don't need to increase it. If it's too high, then you could still get scaling. If you have plaster or fiberglass, then use The Pool Calculator to calculate the saturation index and increase the CH as needed after all other water parameters are where you want them.

yes its vinyl.... cool thanks

[jeffwltrs]

New Here! I have an amonia problem with my pool water! Pool supply place keeps telling to wait for the amonia levels to reduce on their own. That adding shock would only compound the situation. I opened my pool a month ago and I am still waiting and the levels haven't come down on their own. They say my amonia level is 8+! The pool water looks great and I am running the pump continuously! I have only put in algecide to keep the algae from growing! I have an 18,000 gallon concrete/fiberglass pool in Ohio! Thanks for any suggestions!

[chem geek]

The pool store is absolutely wrong. Ammonia takes a long time to dissipate from the pool and in the meantime the pool is not sanitary because it cannot hold any chlorine. Though you could try aerating the water to outgas the ammonia, I think that's going to be impractical. Algaecide can keep the algae from growing too quickly -- I hope you aren't using an algaecide with copper metal ions (such as copper sulfate pentahydrate) as that can cause staining or discoloration of the water or greenish hair. If you want to use an algaecide, use PolyQuat 60.

To get rid of the ammonia, you need to add an oxidizer and 10% or 12.5% chlorinating liquid or 6% unscented bleach is the least expensive way to do that -- non-chlorine shock costs much more. However, 8 ppm ammonia would require at least 60 ppm Free Chlorine (FC) cumulatively added and it may take a lot more than that if the ammonia level is much higher or there are other partially oxidized fragments of Cyanuric Acid (CYA). Apparently, you let your pool go over the winter and when the FC went to zero some bacteria converted CYA into ammonia. This is described technically in this post and my own experience with this is described in this thread.

With the rather high ammonia level in your pool, you are probably better off doing a lot of water dilution/replacement. It depends on the cost of water vs. chlorine. If you want to estimate how much chlorine it will really take to clear your pool, you can do a bucket test where 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm FC, so 1 teaspoon is 40 ppm FC. You can see how much chlorine needs to be added until the FC holds. Note that initially the chlorine will get consumed quickly and get to zero probably within 10 minutes and certainly within an hour (assuming your CYA level is at zero), but after the ammonia is oxidized completely the FC will get consumed more slowly but will still be dropping. When the FC holds for several hours without dropping, that tells you how much you need to cumulatively add to the pool -- I suspect it's a very high amount which is why water replacement/dilution would probably be more economical.

To prevent this problem in the future, either maintain an FC level over the winter or if you are in an area where the water freezes over, then maintain an FC level until the water gets below 50ºF (or lower, if possible) and then shock the pool to have 10-15 ppm FC and then reopen the pool before the water warms up above 50ºF (preferably lower) and add chlorine again if needed. You can also use PolyQuat 60 upon closing, but that needs to be very well circulated in the colder water and by itself probably won't last the winter and it will break down from some chlorine as well.