Can Ph be too high and what is the number in which it becomes a problem?

[Reef Puncher]

So a while back i suffered from low ph. I swapped from 2 part to kalk. i instantly went from 7.9 to 8.2 during day, and at night it was around 8.1. i wanted to get it a little higher, so i bought a CO2 scrubber for my skimmer. But the problem is its working a little too good. During peak light it reaches all way up to 8.58 which seems a little too high. At night its around 8.4 which is fine. But im tempted to unplug CO2 scrubber or use vinegar. Its just gonna be a pain to reconnect all the old venturi system but i will if this is too high a ph. im also debating dialing back the kalk....

When does high ph become a problem? Is 8.5 or 8.6 too high?

 

[Randy Holmes-Farley]

The point at which it becomes too high, IMO, is the point where excessive precipitation of calcium carbonate becomes too problematic.

The pH peak you suggest is OK in many tanks. mine typically peaked at pH 8.55 without issue.

 

[Reef Puncher]

The point at which it becomes too high, IMO, is the point where excessive precipitation of calcium carbonate becomes too problematic.

The pH peak you suggest is OK in many tanks. mine typically peaked at pH 8.55 without issue.

haha your fast, i just mentioned this thread to you and you had already responded.

I always see people mention precipitate. never fully understood it. Do you mean i will literally see like calcium crystals forming on something? like glass or something?

 

[DanyL]

I agree with Randy.

Personally for me, the tipping point is around 8.4, at which dosing concentrated Sodium Hydroxide brings the PH just enough to cause precipitation.

So it depends how high your PH will get *locally* (in this case - the chamber where I dose Sodium Hydroxide) which would determine the tipping point for you.

 

[DanyL]

Do you mean i will literally see like calcium crystals forming on something? like glass or something?

Exactly this.
And it’s quite difficult to stop this once it begins to form. You really need to remove the buildup completely, otherwise it’ll continue growing even at lower PH levels.

 

[Reef Puncher]

I agree with Randy.

Personally for me, the tipping point is around 8.4, at which dosing concentrated Sodium Hydroxide brings the PH just enough to cause precipitation.

So it depends how high your PH will get *locally* (in this case - the chamber where I dose Sodium Hydroxide) which would determine the tipping point for you.

so do i look for precipitate where my doser drops the kalk (the return chamber in sump), or in the display tank?

 

[Randy Holmes-Farley]

haha your fast, i just mentioned this thread to you and you had already responded.

I always see people mention precipitate. never fully understood it. Do you mean i will literally see like calcium crystals forming on something? like glass or something?

Signs are hardening sand, and excessively fast development of deposits on warm objects such as pump impellers and heaters (some is normal).

Visible white precipitate in the tank (even turning the tank to milk) mostly seems to happen in sudden large overdoses of things like kalkwasser, although it can happen locally:

What is that Precipitate in My Reef Aquarium? by Randy Holmes-Farley - Reefkeeping.com

Figure 4. When limewater drips onto surfaces, such as the sides of a sump, precipitation of calcium carbonate takes place. The off-white coloration probably comes from metals such as iron binding to the calcium carbonate surface in the place of calcium.

 

[Garf]

haha your fast, i just mentioned this thread to you and you had already responded.

I always see people mention precipitate. never fully understood it. Do you mean i will literally see like calcium crystals forming on something? like glass or something?

My water gets misty at >8.55pH, so I restrict it to 8.4

 

[DanyL]

so do i look for precipitate where my doser drops the kalk (the return chamber in sump), or in the display tank?

In my case it was - mostly because it was local, but it isn’t restricted to this area alone.

Randy beat me to it and gave quite a few more examples.

 

[GARRIGA]

Is there an additive that would reduce the ability to precipitate at higher pH values? Would higher levels of magnesium, for example?

 

[Reefering1]

Is there an additive that would reduce the ability to precipitate at higher pH values? Would higher levels of magnesium, for example?

Phosphate (?)

 

[GARRIGA]

Phosphate (?)

But will that reduce it because it binds to it? I'm wondering if there's something that can prevent it. Thought magnesium had a role in controlling that.

 

[DanyL]

I know Magnesium Hydroxide formulated momentarily when dosing high PH additives. Not sure how it would relate to Calcium Carbonate participation though.

 

[GARRIGA]

We know low magnesium allows precipitation to occur therefore my thought process being excess does the reverse but that's just guessing.

 

[Reef Puncher]

Is there an additive that would reduce the ability to precipitate at higher pH values? Would higher levels of magnesium, for example?

i actually read an old post of Randys where he said you could add one ml per 10 gallons of white distilled vinegar to reduce it. i may have to try that.

 

[GARRIGA]

Acid reduction

 

[DanyL]

We know low magnesium allows precipitation to occur therefore my thought process being excess does the reverse but that's just guessing.

Yes, it makes sense - though wouldn’t that mean that it was missing in the first place?

i actually read an old post of Randys where he said you could add one ml per 10 gallons of white distilled vinegar to reduce it. i may have to try that.

I mean, sure - but it’ll also make the water more acidic which sort of defeats the purpose to increase PH in the first place.

 

[GARRIGA]

This is why the chemistry part of reefing allures some and yet strains my brain wanting less complexity and would be nice if those sea shells actually worked although just like in Demolition Man, no clue what exactly they do

 

[Garf]

We know low magnesium allows precipitation to occur therefore my thought process being excess does the reverse but that's just guessing.

Magnesium bible;

Aquarium Chemistry: Magnesium In Reef Aquaria

This article details the nature of magnesium in seawater, how it is added, measured, and removed from marine aquaria, and how it impacts the maintenance of calcium and alkalinity.

reefs.com

 

[Randy Holmes-Farley]

Is there an additive that would reduce the ability to precipitate at higher pH values? Would higher levels of magnesium, for example?

Yes. Many organics, phosphate and magnesium all help. Sodium polyacrylate stopped it entirely in my nontank tests until supersaturation got so high it crashed out all over.