automatic water change

The automatic water changing systems described on the web intrigue me. Due to chloramines used in my area I will have to pump dechlorinated water from a garbage can or 45 gal drum to 6 to 8 tanks. A pond pump or the like seems like the way to go. Dose anyone know if the backpressure created will have any adverse affects on the pump?

You might include some links so we know what systems you're considering. Every pump has a specification for its flow rate as a function of head pressure. In occasional use (as I think you're planning), I think the chances of harm to the pump are minimal. If you get water from the hose, it works ;~). In most designs, if the head pressure is too high, the impeller just spins, and you wouldn't let it run like this for hours. Pond pumps often have this data somewhere in their documentation, showing how much the flow is reduced for every inch above the surface of the container you are pumping to.

Thanks for the link. Always interesting to see home-brew systems. Some parts looked a little too DIY-garage but on closer scrutiny, you can see that it was thought out (imo), and simplicity *is* the key (not cosmetics).

Incidentally, Centaur activated carbon is the grade recommended for the removal of chloramine from municipal supplies. Regular carbon works as well, but will exhaust itself faster (in theory, but I was quite satisfied with it's performance using an average source of 2.5ppm (5ppm peak) mono-chloramines). Slow even flow rates through the carbon helps in the adsorption.

This will probably solve your pump question ;~).

You seem to be suggesting that if the water was filterred through Centaur, I would not have to store and treat it. Tap pressure would replace a pump. I thought that carbon was not effective with chloramine and that more than filterring was needed. If not, the system just got simpler. Thanks, Bob On Tue, 1 Mar 2005 20:44:16 -0500, 'NetMax'

You got it. Many commercial installations use carbon to remove chloramines. Get a hold of an ammonia and a chlorine tester, as this is the best way to know when the carbon has saturated. I would get about 16 months out of 2 cu.ft. of regular carbon, but I was doing *huge* water changes 4 times a day. There are also carbon additives sold specifically for commercial aquaria to remove more than the usual stuff, but I didn't think our water source was bad enough to warrant the extra expense. Just remember that your flow per cu.in. should be relatively slow for carbon filtration to work well. Depending on your chloramine concentration, you will be releasing some ammonia into your system, which with a properly sized filter system is not a problem, and it makes good plant food.

Thanks for the input Max. Bob On Wed, 2 Mar 2005 17:39:28 -0500, 'NetMax'