How do I pick my goal # for ALK?

fishbox · Feb 21, 2018

Let me start by saying that chemistry is a foreign language to me. Yes I've read several of Randy's articles and quite a few posts here on the forums but I'm still trying to figure it out lol.
I know Randy says between 7-11dkh, but if my ALK is 7 one day, and 11 the next, is that ok or too much of a variance or what's considered too much of a variance? I see some people choosing a number in between Randy's recommendations and striving to stay as close to that number as they can. Then I seen comments about trying to match your salt. Well I am currently using IO but will probably switch to Fritz soon. I read IO usually ends up with the ALK being between 10-11. But then I seen one of those poll threads and I think the majority of people were keeping their ALK around 8.5.

wattson · Feb 21, 2018

Sagecritter4life · Feb 21, 2018

Not much help since still figuring it out myself but my LPS like a DKH about 8.2 after trial and error and most all professionals recommend not more than 1 DKH a day either way and stability is important.

I was using Red Sea Pro but after realizing they liked lower DKH “for my lighting and nutrient levels” I switched to blue bucket which mixes about 8.3 at 1.026 so much closer to stabil for me. I also use about .o9 DKH daily and dose Randy’s/brs two part to keep it there.

Just newbie myself though and following also ;-)

Kershaw · Feb 21, 2018

You do not want your all going from 7 to 11 in one day.
Stability matters most.
What I do is do a water change and see where your alk is. If it’s between 7-11. Try to keep at what ever number it is. Then over time you can modify this number as to try and achieve the best health of tank. Must go slow when messing with alk. Or anything in this hobby

Daniel@R2R · Feb 22, 2018

This should be a good discussion. I think a lot of this is a combination of factors that impact how alk is taken by the corals and at what levels they seem to be healthiest in your tank. This will depend, in part, on nutrient levels, types of coral, etc. @Randy Holmes-Farley will be the one to provide an expert answer (and hopefully correct anything I've gotten wrong here).

fishbox · Feb 22, 2018

Kershaw said:
You do not want your all going from 7 to 11 in one day.
Stability matters most.

I kinda figured that would be the case but that still leaves the question of what my goal should be.

My tank is a little bit over 1yr old. It's a 40B with a 20g sump. I rarely tested ALK and never tested Ca because up until recently I only had 3 corals. I only tested ALK like every couple weeks and it was always around 9-10. A few weeks ago it dropped down to 6 and it's been stuck there. I think due to the addition of my chaeto reactor. I wanna step up my coral game. So I wanna get this figured out. I purchased a Salifert Ca test kit yesterday and that turned out a little low as well about 350.

wattson · Feb 22, 2018

start with testing Mag first,adjust that first if need be ,then test for Cal and Alk afterwards....

fishbox · Feb 22, 2018

wattson said:
start with testing Mag first,adjust that first if need be ,then test for Cal and Alk afterwards....

My LFS was out of Mg tests so she ordered one for me

Fourstars · Feb 22, 2018

I haven't tested my levels for a while because everything was looking great and the SPS were growing like weeds. Then noticed the softies were not opening so I tested and found the AlK at 12.5 MAG at 1500 and CAL at 500 plus. Yikes! I have mixed up a batch of reef crystals and used muriatic acid to bring down the ALk to 5. I will change 5 percent every three days to get it down to the point the softies improve and then keep it at that level. I'm going to use my green star polyps as a gauge on the highest ALK level I can maintain since I have such fast growth of the stoney's at elevated levels.

drawman · Feb 22, 2018

As others have said stability matters most. I think alkalinity in the lower range (7-9 dKH) is somewhat easier and has less margin for error for SPS systems. This is especially true if your nutrients are on the lower side. That said, some report greater growth at the higher end of the spectrum.

I've run both sides of the spectrum myself and prefer the lower end for my SPS coral. I can get away with a lot more when it comes to LPS and I never really keep soft coral.

Randy Holmes-Farley · Feb 22, 2018

In general, if you want faster skeletal growth of hard corals, higher alk and higher nutrients (sufficient N and P of some form) to go along with it. Maybe 10-12 dKH.

If you keep nutrients lower for any reason (or you just don't measure them so they may be low or get low), then lower alk (say, 7-8 dKH) is better since higher alk and lower nutrients can lead to SPS burnt tips (which may be due to the skeleton growing faster than tissue can keep up).

If you are keeping primarily LPS and soft corals and anemones and such, I'm not sure the alk value matters much within the normal range of about 7-11 dKH.

fishbox · Feb 22, 2018

Randy Holmes-Farley said:
In general, if you want faster skeletal growth of hard corals, higher alk and higher nutrients (sufficient N and P of some form) to go along with it. Maybe 10-12 dKH.

If you keep nutrients lower for any reason (or you just don't measure them so they may be low or get low), then lower alk (say, 7-8 dKH) is better since higher alk and lower nutrients can lead to SPS burnt tips (which may be due to the skeleton growing faster than tissue can keep up).

If you are keeping primarily LPS and soft corals and anemones and such, I'm not sure the alk value matters much within the normal range of about 7-11 dKH.

Thanks for chiming in Randy. That helps a lot.

John3 · Feb 22, 2018

I can only comment on lps and softies but from what I see in my tank if nutrients are higher I can run higher alk(11-12) and run my lighting a little higher and I get really fast growth.

So you really need to plan on how you want to run your tank and then tie in the water parameters and lighting. Once you find your sweet spot then just try to keep it as consistent as possible. For example if I let my alk drop below 10 my corals look like crap. If my nutrients drop out my corals look like crap.

It sounds like a lot to worry about but once you get to a sweet spot the work becomes a lot less. I now have my manual dosing schedule down pretty good and I test once a week. Rarely do I need to adjust anything anymore. It’s taken me a year to get to this point and I think that is fast because of all the info and help you can get here.

wattson · Feb 22, 2018

Wonder what does the consensus of everybody think Alk level would be best in a system that has No3 -20ppm and Po4-.07 should be ?
In a tank that is all softies that are zoas/Palys..with MH and T5 lighting.
curious to hear what people think the sweet spot for Alk should be .

John Lohsr · Feb 22, 2018

I have a 90 mixed reef, a few sps, afew lps and a few softys. If I dont dose alk, cal and mag my tanks alk drops to in the 6s. But it also depends on how much coraline algae there is. I clean the back glass every couple months and my alk consumption goes down. I try to keep my alk at 9.5 seems like what corals I have likes it there. I check my alk on a daily basis to stay in tune with my tank.

cracker · Feb 22, 2018

I haven't graduated to lighting & Alk levels yet. So I shoot for ALk of 8.0 & just dose the same amount of CA. Iv'e tested every night for months . Just tonight I did a 2 week average on what I dosed every night. I'm going to start dosing this amount for a 4 or 5 days (regardless what the nightly tests say). Just to see if I get an average of the 8.0 I'm shooting for.
So fishbox , pick a desired level & try this. I for one would like to see what Ya get. Maybe get that worked out then work on other nutrient levels to match? will watch this thread to see.

Ferrell · Feb 22, 2018

Following
My question is in the stability. I know in a perfect world stability would be a #.# all the time but as we know it never is. What would be considered a safe variance in Alk to be considered stable?
Also my Mg has ALWAYS read high over the Red Sea Pro test kit. Have never dosed, only kalk.
HW reefer salt. Why such a high reading and how do I lower without crashing all the others? Water changes don’t change it

fishbox · Feb 22, 2018

cracker said:
I haven't graduated to lighting & Alk levels yet. So I shoot for ALk of 8.0 & just dose the same amount of CA. Iv'e tested every night for months . Just tonight I did a 2 week average on what I dosed every night. I'm going to start dosing this amount for a 4 or 5 days (regardless what the nightly tests say). Just to see if I get an average of the 8.0 I'm shooting for.
So fishbox , pick a desired level & try this. I for one would like to see what Ya get. Maybe get that worked out then work on other nutrient levels to match? will watch this thread to see.

Well I don't have many corals as of yet. And out of the one's I do have, only two are SPS. that combined with the fact that my N&P are on the lower side right now, I'm thinking that I should be good around 8. Sounds like I'll just have to keep an eye on things as my collection grows and make adjustments as needed.

tgionet · Feb 22, 2018

I always recommend shooting for what your salt mixes up to

ReefBeta · Feb 22, 2018

tgionet said:
I always recommend shooting for what your salt mixes up to

Second this.

As long as your salt mix result in a reasonable level, like anywhere between 7-11dkh, it's best to start with keeping within 0.5 around that level. Stability is way more important that the actual level. High fluctuation of Alkalinity is way easier to stress or even kill coral. Lower or higher but stable level will only cost you marginal grow speed if any. Once you mastered that you may consider adjusting it to higher for potentially faster grow.