Well after many months of water changes using synthetic, i was finally able to collect 250L of NSW on saturday. The reason i needed it was because i added a 6ft frag tank to my system to replace the 5ft which is on its way to the office to set up a fish only system there. Will be interesting to see if the growth rate on the corals improves again. First thing i noticed, the ph was slightly down on yesterday and my alk had dropped from 8dkh to about 6dkh.