Caliban wrote: > I am honestly still amazed that using lab grade chemicals generates the amount of controversy that it does! :lol: Dosing, purity, testing, etc. seems to be pretty common in the marine/reef side of the hobby Using reagent grade chemicals isn't something that should be controversial. You are free to define your problems any way you want. It is more troublesome when people start recommending to others that they *should* use reagent grade chemicals or face a host of potential problems, as one did in the Planted Tank thread that was linked earler. The same thing can be said for most any other relatively extreme measure, like using only RO/DI water. Relating practices used for freshwater aquariums to those used in reef tanks always seems to be a problem. The marine environment tends to be pretty stable; ocean water compositions don't change much over time and tend to be fairly constant from place to place, temperatures change only gradually, currents are regular or subject to tidal occilations -- especially at depths below the reach of waves. Also, sea water tends to be very poor in metals and many nutrients. Constant and sometimes extreme changes are a hallmark of the freshwater environment, with rapid and sometimes extreme changes in every physical and chemical measure. Moreover, what is called fresh water in one locale may have little chemical resemblance to fresh water from another locale. Metals and nutrients are frequently much higher in freshwater than in sea water. While for salt water tanks there may be some reason to stress constant conditions and to use reagents that are very low in contaminants, those reason's aren't as important to fresh water tanks -- particularly when the "contaminants" in question are just chemicals that would occur naturally in the water anyway. Just a couple comments on your methods... You regularly monitor and adjust levels in your tank, so the purity of the chemicals you use and the accuracy of the doses seem to be of little importance. You can get the same result with or without high-purity reagents. Second, I expect you know that the reagents used in test kits are not completely stable -- some of them are quite unstable. The results from a single test kit applied to a standard should drift over time as the reagents change. You probably already know this, but others may not; if you adjust your water composition so that the kit always produces the same results, then the composition of your water is probably drifting. It is pretty common for people to replace an old test kit and find very different results from the fresh kit. Roger Miller -------- Technique, technique, technique -- Isabella Guerin, 2001 -------------------- m2f -------------------- Read this topic online here: http://forum.aquatic-gardeners.org/viewtopic.php?p=1520#1520 -------------------- m2f -------------------- _______________________________________________ AGA-Member mailing list AGA-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/aga-member