Ideal Alkalinity for SPS growth?

SamMule · Jul 4, 2020

I seem to find a lot of contradicting information.
Some say high, like 10dkh (red sea)
Others say low, like 7.5

I'm keeping mine at 9.5 right now. My SPS all seems happy. I see a lot of people talking about tip burn with high alk. My nutrients are pretty low and consistent. .03 phosphate and 2 ppm nitrate.
According to some of the stuff ive read, my acro tips should be burning.
What am I missing?

TheGreatBarrioReef · Jul 4, 2020

I keep mine at 8.3. The key is to keep it steady at whatever value you choose

Kyl · Jul 4, 2020

If there is one thing I've learned over the past 6 years, it's that there is no ideal. Every tank is different, even separate tanks in the same room are different.

Asagi · Jul 4, 2020

SamMule said:
I seem to find a lot of contradicting information.
Some say high, like 10dkh (red sea)
Others say low, like 7.5

I'm keeping mine at 9.5 right now. My SPS all seems happy. I see a lot of people talking about tip burn with high alk. My nutrients are pretty low and consistent. .03 phosphate and 2 ppm nitrate.
According to some of the stuff ive read, my acro tips should be burning.
What am I missing?

Turn your doser off for a little bit. Get that alk down under 9.

Jfarooqpak · Jul 4, 2020

So you have no tip burn AND your corals are happy? What is the question again? Sorry i dont get it

robdareefer · Jul 4, 2020

The higher the ALK the faster the skeleton growth, if the the other perimeters that contribute to the flesh growth are low such as po4 and no3 then the flesh can't keep up with the skeleton then the tips get burnt because the flesh is to thin on tips.

pdxmonkeyboy · Jul 4, 2020

Also with nutrient levels that low... there is very little margin before you get in the "crash zone".

The thing about alk... there are risks associated with running it higher (like how do you not shock the bezeesus out of new corals) but there is little risk at all too keeping it atound natural seawater levels.

I try to never go above 9 myself.

joseserrano · Jul 4, 2020

where you keep your Alk is highly dependent on nutrient levels and par levels

anth · Jul 4, 2020

joseserrano said:
where you keep your Alk is highly dependent on nutrient levels and par levels

This couldn't be mire true for me.
I have the same nutrient levels os the op and i keep my alk at 7.2. Great colour and growth.

ycnibrc · Jul 4, 2020

Well this topic is very hard to answer because each tank are different however for me natural sea water parameters are the best because corals dna has been mold through out millions of year to grow in it. The environment of reef aquarium is different and thats why we have slowed grow when we first introduce a coral to our tank.

FMF0331 · Jul 4, 2020

SamMule said:
I'm keeping mine at 9.5 right now. My SPS all seems happy.

If it's not broken , don't fix it .
Again ... not all tanks are the same, my DT is reading 7.7 and growth is amazing. My frag tank is 8.6 and every frags seems happy.
Enjoy what you got going on , sit back and enjoy the show.

SamMule · Jul 4, 2020

This is all really great information. I appreciate the input!

X-37B · Jul 4, 2020

In my area most run alk at 9-10. Two lfs out of 3 run 10. The other 8-9.
Ask them why and one says it gives better growth and the other says its never above 9, your test must be wrong lol.
I ran mine at 8-8.5 for the first 6 months then lowered it to 7-7.5 and have seen better color, and growth has not changed.
Po4-.02-.04
No3- 2
Like above advice pick a range and not a number and keep it their.
Your corals will be happy with a stable range regardless of the number within reason.

TX_Punisher · Jul 4, 2020

Just bumped mine up to 9.5 after a few months at 9. Alk is constantly dropping this week with kalk and ca reactor which tells me things are growing.

Softhammer · Jul 4, 2020

The ideal alkalinity is whatever value you can keep stable.

SamMule · Jul 6, 2020

Perhaps I spoke too soon. Woke up this morning and saw this on my acro. Not sure if this is tip burn or new growth? I can see a polyp extending out from the tip.

Measured alk last night at 9.3

C. Eymann · Jul 6, 2020

Ideal # is dependent on nutrient level, seems you already understand that though.

9.5dkh with 2ppm /.03 is really riding the edge.

If that is your target N/P Id go no higher than 8.0-8.3

Unless you want to test PO4 /NO3 3 times a week to ensure they dont drop/bottom out leading to burn.

Running an alk of 9.5 vs 8.3 wont be worth the potential slight increase of growth rate.
You want a bit of a cushion there,

Of course, probably sounding like a broken record, but STABLE alk level is the key to sps happiness and happiness =fast growth.

SeaDweller · Jul 7, 2020

I haven’t had issues never going over 7.5-7.6 dKh, so I don’t see a point going any higher. Personally, I wouldn’t want to go over 8.0, I just don’t see a need to.