Reynbob

Biodesign pools have a porous material layer over a Goodyear rubber liner. That material allows the weight of the water to rest directly on the liner therefore Biodesign pools have no rebar or gunite. The porous material can allow minute organics (pollen & algae) to settle onto and seep down to the top of a hidden liner. The pools are not holding chlorine. Could it possibly be ammonia coming from the decomposing organic matter? This organic matter is very difficult to remove and will not vacuum up. It is my understanding that ammonia will bind with chlorine very quickly. On a 9,000 gal Biodesign pool ... add 10LBS cal-hypo... and within hours ZERO chlorine. Would anyone know if Bromine is affected by ammonia in the same way? I am just assuming ammonia because we have drained, pressure washed, and refilled several of them. As it's being washed (walls/floors) a greenish black sludge is washed to the bottom MD. We are in central TX and an area of pretty heavy Oak pollen. General water chemistry (pH, Alk, CH) is maintained. I do not see any topics related to Biodesign pools on these water forums. Thanks. Pool Builder in Texas.

Thanks for the quick response Chem Geek....I would suppose being better safe than sorry would be appropriate for fiberglass pools....unless the pool owners knew the composition of their shell or were so inclined to find out. In most cases I doubt this would be the case. I also noted that there was no link on the see-this-post on your vinyl liner response....I would be interested to see that also please. Thanks again for the response....

Long time forum follower....new registered user. I own and operate a small town retail pool store and have been following the advisement of the water-wizards on this forum for some time. Including the advisement about calcium hardness in fiberglass and vinyl pools. In other words...not really necessary. For back ground, one rural water provider in this area has very soft water....in the 12-20ppm CH range....very soft....Our chemical supplier is insisting on the need for calcium hardness in the standard range that most water testing applications ask when testing fiberglass and vinyl pools. He went so far as to state that low CH could or might crack a fiberglass pool. I do understand the need in plaster pools and I do follow NPC guidelines on new turn-ups...or as closely as practical considering they were drafted by a "committee". I would like to know if standard fiberglass/vinyl CH levels are indeed absolutely necessary or not. I trust you guys and I want to do the right thing for my customers. Please advise and thanks in advance.