Low Alk, bad response trying to raise

[tanksoftwiddy]

Hello all

I have a 220 mixed reef tank stocked with various SPS, LPS, softies and fish. I currently have:
Clown Trigger
Niger Trigger
4 lyretail anthias
2 flash percs hosting my hammerhead
2 firefish
Six line
Yellow tang
Blue hippo
Mandarin

I also have a 5 inch clam my wife gave me for my birthday 12 months ago (unsure what she bought) . I believe it's a Derasa from research.

A few months ago my alk was testing fairly low, around 6.2-6.5. Calcium was testing consistent 430-450 and Mag was low, around 1230 or so. I have gotten my Mag up to 1350 and can maintain calcium but cannot keep my alk up above 7. I am using all BRS two part solutions.

On top of that, my clam seems to be struggling since I started dosing and my coral growth has slowed.

I run biopellets and gfo, and carbon every now and then and have been fighting algae for about 6 months.

I'm getting towards the end of the algae issue, but can't seem to figure out why the clam and corals are struggling while trying to raise the alk. It makes me think, especially while running biopellets, my alk being that low is ok, but that doesn't really explain the algae issue.

Sorry, lots of info, but any thoughts?

 

[rayn]

Doing a lot of reading here lately in research for my build and I keep coming across a ULNS not needing the higher alk. What are you nitrates and phosphates at? What type of algae and how have you combated it?

 

[tanksoftwiddy]

Nitrates are not measurable. I have a 3 chamber sump with a fuge. Chaeto grows pretty well and I harvest it every week to keep it around softball size.

Phosphates vary from test kit to test kit to the point where I stopped measuring. My assumption, if I have algae, I have phosphates.

I have read a lot about that as well.

The algae is a green hair type, but easily removable which has been my method of removal. I have picked up my tank work in the last 3 months and it has greatly helped.

I run barebottom and have moved my flow around to pick up more detritus.

I can explain the algae reduction, but hard to explain algae in an ULNS right?

 

[rayn]

Well yes and no. ULNS just means they aren't detectable to me, not that they aren't there. I'm fighting HA now myself in a 20. I've got more stuff hanging off of it then I ever dreamed. Filter, skimmer, reactor. All to keep levels low. But with algae growing, they are taking some of the nutrients up. Mine all register 0 as well, but something is feeding them.

How much are you trying to raise at a time? 1.4 dKh a day should be the most. If you are going over that you may be shocking them.

 

[tanksoftwiddy]

I'm not raising it very quickly. Maybe . 5 dkh a day at the most. More of an issue maintaining it high.

 

[rayn]

That may be part of the issue. If you aren't raising it enough it is still getting used and you aren't giving enough. Once you get it high you need to figure out your maintenance dosage to keep it there.

 

[tanksoftwiddy]

Sorry for long response. I purchased a new dosing system to help me make things a little more regular. hopefully that will help keep it up.

Thanks!

 

[Randy Holmes-Farley]

When you say you can get the alk up, what does that mean?

You start at what dKH, add how much, then remeasure how long after?

It is normal for alk to drop 1-4 dKH per day in a typical reef tank. 0.5 dKH is likely just below the demand.