ULNS and Alk

[beatle]

I have what I think is a ULNS with my nitrate at 1.82 and phosphate currently at 0.0, each measured on a Hanna low range checkers.  My Alk is 10.1 but has been as high as 10.7.  I'd been raising it from 7 over the course of a few weeks in hopes of getting better growth, however my SPS are starting to burn and fade.  My salinity has also crept up to 1.027 recently (usually 1.026) and I am also currently acclimating from 50-150 PAR to 150-250 over the course of a month (currently 10 days in).  So I have a lot of variables changing at once since they are all out of whack.

 

Anyway, I think nutrients are a problem that I do not yet have a solution for.  I've read that a ULNS shouldn't have high alk, but what's considered high for ULNS?  I've read anything between 7 and 12 is acceptable.  I'm a little higher than halfway, but given my current state of affairs, I think I need to change things up.  To add nutrients, I am planning to feed a bit heavier - currently only feeding corals once a week (up to twice) and will give the fish a little more LRS each day.  In the meantime I'm curious to know what a good alk value is for my current nutrient levels.

[wildcrazyjoker81]

It has been my experience that tanks just don't really like ULNS with higher alkalinity. I honestly really haven't found a reason to keep alkalinity much about 8-8.5 regardless of nutrient levels. I feel like the best growth I have had is between that 8-8.5 with having a good PH between 8.2-8.3. PH of course is one of the hardest things to manage typically in the hobby. I also never have great luck personally with running lower nutrients. More vibrant colors with Nitrate above 5 and phosphate above .03. I say all of this of course with the caveat that every tank is vastly different and it is always a contentious point when brought up. I feel like it is similar to asking "what is the best salt for a reef tank?" 

 

That all said I would probably lower your alkalinity levels and feed a little heavier as you had mentioned.

 

 

[beatle]

Sounds like even 10 is "high" alk.  Seems like running the higher nutrients necessary to also run high alk seem to be risky since algae can also bloom under higher nutrients.

 

I did see a bump in phosphates by feeding coral twice a week so that'll be my plan for now.  Hopefully any increase in algae is controlled by the snails I added back in December.

[Origami]

You'll want your alk under 8.5 for a ULNS system. "Burnt" SPS tips are typical when this guideline is exceeded by much. To be safe, keep it at 8 or lower.

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