Originally Posted by
crustaceon
Some thoughts:
If your LPS is doing fine under the AI, it’s probably not too crazy for your SPS at that setting.
Crazy high alk needs crazy high nutrients. If you’re feeding that little, I would recommend dropping the dkh to 8. I’m sitting at 7 dkh with 2.5ppm nitrates and undetectable (still present) phosphates and my sps is bright and growing well. My tank isn’t heavily stocked...yet. If I were you, I would start by determining your exact nutrient level and see where that slots in with your alk. From what i’m reading and seeing your stocking, you would be better off running a more reasonable alkalinity level. That can of course change as your tank fills with corals and you become one of those “coral gurus” who swears by a dkh of 12, feeding 17 times a day, not using a skimmer or algae scrubber and gets 1/4” of coral growth per week.
That 34 gallon only needs around 2000 gph of indirect flow and even that may be pushing it. That would give you 60x turnover. I’m not sure what pumps your big tank was running but you might want to dial it down if you were using mp 60s or gyre 280’s. As far as flow direction goes, I’m willing to bet most people have their pumps going at one speed all day long, are having no problems and only turn on the “wave mode” to show off to guests. As long as the flow isn’t directly blasting your corals, you’re probably ok and the fact that wave makers haven’t been around as long as people have been successfully keeping coral tells the tale.
IMO, you’re probably shocking your corals to some degree with the volume and frequency of your water changes. As stated, even small but rapid alk swings can weaken sps and make them more susceptible to illness which turns into burned tips or rtn/stn. As your salt is inherently adding way too much alkalinity during water changes, you could counteract this by doing multiple smaller water changes stretched out over the week and for a smaller percentage overall. I actually started with a 34 gallon bowfront and did a ten percent water change over the week. That 3.4 gallons of water was extracted while siphoning sand in a grid pattern every day. A little bit of water out and a little bit of water in. It worked extremely well for me and best of all, it put very little stress on my corals.
Seeing that you’re pretty diligent with maintenance, I also wouldn’t he surprised if your water was “too clean”, which would absolutely cause issues in more sensitive corals in the stated time frame. A nitrate and phosphate test will tell the tale.
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