Trying to wrap my head around these levels

[Sticker shock]

Here's my recent testing. I'm not sure why my pH is hovering around 7.7 to 8.
9/5 started dosing Magnesium trying to lift the levels to around 1350
9/7 started dosing nitrate
I have a macro reactor running with Cheato

Any reason to worry about this lowish pH?
Is Alk constant enough
Also today tested Mag using a new Hanna checker vs Salifert - Hanna shows 1430 Salifert 1300 (as a result I'm going to hold off on trying to raise Mag any higher.
Overall am I on the right track here?

 

[hexcolor reef]

I had/have the same issue with PH dropping into those ranges. Could be from organic matter building up which create an acidic environment. Clean sand bed more.

Your ALK levels look to have gotten pretty stable. Nitrate is to low. Data looks to be from a new tank.
Your tank is on the right track.
Mag can be dosed to bump to 1500(Hanna) and to put 1350 (salifert)

I keep my Mag at 1500/calcium 500

As far as PH it will fluctuate a lot. My corals didn’t like it so I started dosing PH to keep PH around 8.2-8.4. Took a bit of trail and error with dosing set up but I pinned it.

 

[Sticker shock]

Yeah, my tank is coming back from about two year lack of care, so there is a lot that has been going on lately:

Zombie tank, can it be saved

I have a 75 gallon reef. It’s been about 2 years since I’ve done more than top off and feed. It’s a nightmare…tank is like the walking dead, somehow staggering forward when it should have been dead and buried. What happened was, my oldest daughter got sick and my tank became something I just...

www.reef2reef.com

I know the nitrate is low and recently started dosing to correct this. I've been cleaning the sand bed slowly but surely, but all the water changes are starting to get pricey so I've slowed down on those. I'm trying to keep it to 10-12 gallons every 2 weeks for now. I was changing that much every other day when I started to fix all the issues I had.

 

[EeyoreIsMySpiritAnimal]

pH looks fine to me... what time of day are you testing?

 

[Sticker shock]

pH looks fine to me... what time of day are you testing?

10am ish

 

[EeyoreIsMySpiritAnimal]

10am ish

And what time do your lights come on?

Do you have a fuge and if so, are you running the light all night?

You may be testing at a point where the natural daily pH swing is low(er).

Try testing in the late afternoon or evening before your lights start to ramp down.

 

[bushdoc]

^^^Exactly, my pH is lowest around 10am and highest around 19:00-20:00. (pH 8.07-8.29).
pH is also affected by CO2 level in the surrounding air, so if your tank is in a small room, but with big family and low ventilation, your pH will be lower.
What method are you using to test pH?

 

[Sticker shock]

And what time do your lights come on?

Do you have a fuge and if so, are you running the light all night?

You may be testing at a point where the natural daily pH swing is low(er).

Try testing in the late afternoon or evening before your lights start to ramp down.

lights on at 8am
I don't have a fuge, but I run a macro reactor 10 pm to 5 am

 

[EeyoreIsMySpiritAnimal]

lights on at 8am
I don't have a fuge, but I run a macro reactor 10 pm to 5 am

Again, I'd test for several days at a much later time.

Even if it's still only around 8, depending on your tests margin of error, it still could be (and probably is) fine.

May I ask: Why are you testing pH in the first place?

 

[Sticker shock]

Testing everything as my tank has been running with nothing but top-off and feeding for the last two years. It's a long story but feel free to read up on the thread I linked. I have no idea what the normal range for my tank is yet and as I make changes I want to make sure nothing gets thrown out of whack

 

[EeyoreIsMySpiritAnimal]

Testing everything as my tank has been running with nothing but top-off and feeding for the last two years. It's a long story but feel free to read up on the thread I linked. I have no idea what the normal range for my tank is yet and as I make changes I want to make sure nothing gets thrown out of whack

Sorry, I don't have time to read your thread. But pH is something that A LOT of us don't test... ever.

 

[Reef Stallion]

Sorry, I don't have time to read your thread. But pH is something that A LOT of us don't test... ever.

If you grow LPS/SPS, you absolutely want to check your pH. (IMO)

 

[EeyoreIsMySpiritAnimal]

If you grow LPS/SPS, you absolutely want to check your pH. (IMO)

For more demanding SPS, maybe, but a current nadir value of almost 8 is a pretty good indication that softies LPS, and a lot of SPS will be fine.
Especially since right now the OP is looking for healthy stability, not trying to rapidly increase coral growth...

 

[Sticker shock]

So if pH of about 8 is ok, then I should be fine dosing just Nitrate. Mg, Calcium, and Alk are acceptable levels. I'll just keep an eye on those to see how they test out for the next few days.

 

[EeyoreIsMySpiritAnimal]

So if pH of about 8 is ok, then I should be fine dosing just Nitrate. Mg, Calcium, and Alk are acceptable levels. I'll just keep an eye on those to see how they test out for the next few days.

Sounds good.

 

[Randy Holmes-Farley]

I had/have the same issue with PH dropping into those ranges. Could be from organic matter building up which create an acidic environment. Clean sand bed more.

I do not think that is a typical cause.

If the alkalinity is normal or higher (say, above 6.5 dKH) then pH below 8 can ONLY come from elevated CO2 in the water.

There are two big sources of CO2 in the water. One is aeration with high CO2 air (the usual cause of the worst pH situations) and from metabolism of foods by fish, corals, and everything else in the aquarium.

Yes, there is some tiny amount of CO2 being produced by the metabolism of the detritus in the sand by bacteria and other organisms, but that is necessarily very small compared to foods metabolized elsewhere in the tank, unless you are letting lots of food settle out and pile up on the aquarium bottom.

 

[hexcolor reef]

Yes, there is some tiny amount of CO2 being produced by the metabolism of the detritus in the sand by bacteria and other organisms, but that is necessarily very small compared to foods metabolized elsewhere in the tank, unless you are letting lots of food settle out and pile up on the aquarium bottom.

Correct, that’s pretty much the OP situation. OP left tank unattended for two years. Just didn’t want it to go unmentioned so OP can use all information given here to tackle the problem