These seem pretty straightforward questins, so I'll take a turn at them: > Questions: > 1. Does a CO2 system is actually needed in hard water, > assuming water is > replaced every 2 weeks and water parameters will not > really change. PH is > rather stable. IN a planted tank the CO2 is a nutrient for the plants, it's presence has little to do with water hardness. > 2. Should I target to higher levels of CO2? (well ph will > slightly drop and > my crypts will melt...) 23 ppm should be a nice level of CO2. > 3. Does any of the other parameters in hard water can > effect the CO2 > dissolved levels ? NO, for an aquatic gardener's intents and purpose no hardness or carbonate parameters affect the amount of CO2 in the water. What they affect is the pH which can throw off the reading onthe CO2/KH/pH table. > 4. In hard water levels I know that some plants will have > trouble processing > the Macro and Micro nutritients. Question is? > 5. FE levels are 0 can there be a process which the FE > will bind itself to > other thing rather than to plants? It's pretty hard for FE not to be cound to something -- which is why chelators (binders) are used in FE supplements -- because they bind it before other stuff does, but the plants can still get it from the chelator. Does your test only test for free FE? You probably want a test kit that can measure accurately with a range that maxes out about about 1 ppm. If the plants are not showing iron deficiency symptoms, forget about the iron levels and think nice thoughts instead, the iron is fine. > 6. Is it correct to link between CO2 levels and hard > water or should I look > for a new direction? Only a small percentage of CO2 in the water forms carbonic acid so only a very small amount can react with carbonates. The more carbonate, the more CO2 reacting with the carbonate--to that extent carbonate levels can affect CO2 levels. *However* in the overall picture, that effect is negligible. CO2 level is essentially a matter of how much you pump into the water, how fast the water is shedding the gas, and water temp, which affects how much the water will hold. sh ===== - - - - - - - - Field Trip to the Baltimore Aquarium and The Aquarium Center First event of the AGA Annual Convention Nov 12, 13 & 14; Details & Registration at www.aquatic-gardeners.org & www.gwapa.org __________________________________ Do you Yahoo!? Yahoo! Photos: High-quality 4x6 digital prints for 25¢ http://photos.yahoo.com/ph/print_splash ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/