Another Low PH question about testing

[Toddah]

I have a IM40 AIO that began 05/24/21. I have about 35 lbs of what started as bleach treated rock from a another users who gave up reef keeping. I added 20 lbs. of Agralive special reef grade sand. started with a bottle of DR. Tims and have been ghost feeding Rods Reef original formula 2 X a week. I seeded Copepods a couple of months ago and have a healthy population on the glass and Amphipods on the rocks and gravel.
No lights ( a few minutes here and there)
No Fish, No Corals
2 Tunze 6055 wave makers on alternating power schedules switching forces every hour (lots of surface agitation)
I had an issue when trying to raise PH by dosing Soda Ash and screwed up my ALK. (got that fixed with water changes)
Still working on low PH issue
A few days ago I turned on my skimmer (Tunze 9004) and I routed a fresh air line from an outside air source. (No real noticeable change after 24 hours)
I am testing PH with my 4 month old APEX PH probe that calibrated successfully (Albeit not without a number of failures)
I am backing that up with a new Salifert PH testing kit.
Salifert kit results in 8.0 PH
dKH =13.0
Not dosing anything
IO Reef crystals in 0 TDS RO/DI water for water changes
PH probe reports avg 7.62, but highs are 7.77 and lows are 7.38
I see lots of "dont chase PH" comments but I would like to know if these numbers are OK.
Should I worry about the Delta between the two tests or manually calibrate the Apex closer to the Salifert test results? or any better ideas how to ease my mind. Trying to do the right thing for my tanks well being.

 

[Queen City Corals]

Hey Toddah, there are a few other factors involved with what pH is desired, primarily what type of coral you are looking to keep, LPS, SPS or softies. If you are keeping softies and a few LPS I wouldn't worry about pH because soft coral won't care at all about your pH in that range. If you are looking to have a large amount of stony corals then you probably will want it at least above 8 for faster skeletal growth. But before you have corals I personally wouldn't even check pH because your corals are going to affect your pH greatly especially as you add more and begin to fill it up. You can get your pH to a perfect 8.3 or 8.5 pH but as soon as you have corals or a refugium all that is going to go down the drain.

 

[arking_mark]

Your cup aeration test is your best tool for assessing your pH.

Take a cup of tank water and aerate it next to your tank for like 30 minutes and measure your pH.

Then take this same cup of tank water and aerate it outside for 30 minutes and measure pH.

If your tank pH is less than cup next to tank pH, your tank needs more aeration.

If your outdoor cup pH is higher than indoor cup pH, you indoor air is higher in CO2 (almost always the case) and you tank needs techniques that reduce CO2 level (open windows, outdoor air feed or CO2 scrubber for skimmer, reverse light schedule refugium, Kalkwasser dosing, etc...).

If your measured outdoor pH is less than 8.1 (it's possible), I'd question the accuracy of testing equipment.

Your actual pH is a function of Alk and CO2. CO2 is very hard to control in a tank and you need very high Alk to get your pH up...so most people just live with stabilizing pH.

 

[Toddah]

Thanks for the input!
I have plumbed a fresh air intake into the skimmer intake line and it made hardly any discernable difference in the PH.
I have 3 Welch springer spaniels, my wife and I living in a ranch style home built in 1984. Tank in in the basement Mancave.
I do see if we go camping for a week the PH will rise in the tank to around 7.8 (Apex PH Probe) or so but never getting into the 8.0 to 8.3 range. I am restarting after a 10 year hiatus and I know when keeping my tanks before (55,60,90,110 and 220) I know I ignored a lot of the finer points of tank testing and maintenance and everything grew and survived OK but nothing like the spectacular tanks I see today.
Now that I am retired I want to dive in deep and try to fully understand the chemistry and balances that make a great tank and habitat for whatever calls it home. I have been dark fishless cycling for 3 months with no lights and just ordered a CUC list last week.
My main worry right now is the differential between the titration test (8.0) and the PH probe (7.38-7.77) , I tend to trust the chemical test more because that's what I am familiar with, the Apex probes are great for quick check and I would love to trust them but alas I was a Sr. controls design engineer for 21 years and will not trust most probes 100%.
My fear is the low readings I am seeing on the PH probes of 7.38 would be harmful to the tank inhabitants.