tazcat

Richard, Thanks for all your help. My background is in electrical engineering, so I need all the help I can get on the chemical side, and you 've certainly been a great resource! Dave

Richard, Thanks for the clarification - I think your last paragraph summed it up well for me. Also, since I keep the pool covered with a bubble-type cover (to retain the heat and control humidity) when not in use, would the outgassing of the nitrogen trichloride be minimized due to the near zero surface area, and therefore have a better chance of being eaten up by the UV system? Dave

Thanks Richard, although I think I'm a little confused now. It seems like adding the CYA reduces the effectiveness of the chlorine, increases the chloramines, but reduces the nitrogen trichloride. Not sure what the nitrogen trichloride is, but I know the chloramines are bad and so I guess the nitrogen trichloride must be worse? Also, is does the UV from the sun affect the chemistry differently than would a UV system (since it only has UV-C)? I read in another post you responded to regarding the difference between FC and active chlorine and how it affects bather comfort, and that's part of my confusion - why not just maintain a very low FC level without any CYA? I'm not questioning the validity, just trying to put it all together. Dave

Yes, I've read that here about the CYA for indoor pools. So let's say I keep 20 ppm CYA, would level of FC would I need to maintain. I'm trying to keep it simple, so I'm just using 12% bleach added to the pool as needed; can the CYA be added in a similar manner? Any down-side to having the CYA in an indoor pool. Also, don't know what effect this has, if any, but the water temperature is maintained at about 85 +/- degeees F (my wife likes it warm....) Thanks, Dave

Thanks Waterbear. You are correct in that I intend on reducing the amount of chlorine needed to maintain the FC level, along with the chloramine reduction given the indoor setting. Also, given a low bather-load of maybe one or swimmers once a day would you expect that 0.5 to 1.0 ppm FC would be sufficent?

Hi All, Just joined the Forum, but been reading here for a while. I have a new, 7000 Gal, fiberglass pool installed indoors and was looking into alternate sanitation methods to minimize chemical use and ongoing expense. I'm seriously considering an Ultraviolet unit to acheive this goal, with the understanding that a small chlorine residual would probably be needed, but much less than normal. My plan is to run a small circulation pump (75 Watts) 24/7 to keep the water flowing through the UV unit (also 75 Watts) at about 15 GPM (total cost about $10 per month in the New England area). Has anybody had experience with UV units in residential pools? I know they are big in the olympic pools, and certainly at waste-water treatment plants, but I'm wondering if anybody can attest to their effectiveness in reducing chemical usage in a residential setting. Thanks, Dave