High pH with re-mineralized water

[SkaleyAquatics]

Hello all,

So I am looking for some advice. But first a little back story, I have a 10g high tech tank that has been setup since December 10th, The last month or so I have noticed a increase in hair/thread algae, I tested my water and noticed my kh was a degree higher causing my pH to be slightly higher and thus my CO2 levels were lower. I decided to start rematerializing my distilled water instead of mixing with tap. But just received the 3 salts required to do this earlier this week. Those salts are MgSO4, CaSO4, and K2CO3. Now onto the problem...

Last night around 5pm, I re-mineralized my distilled water for the first time with MgSO4, CaSO4, K2CO3. I use a bucket to reheat this water, and have a powerhead pushing the water, which is then covered with a lid. This morning around 5:45am I had some extra time before leaving for work and decided to test the parameters of this water. The kh was 3, and the gh was 7, and this is what I was targeting for my water but when I tested the pH it was reading at 8.8 or above. I was just using the API master kit. I was not expecting the pH to be that high. I have a pH pocket meter that I will check with later this evening.

I am kinda lost on how the result of the pH was so high. Does the water need more time to mix the salts in? Could the test kit be bad before its expiration date? Any suggestions or thoughts would be much appreciated.

[Seattle_Aquarist]

Hi @SkaleyAquatics

I believe you are overthinking this.  First of all a 1.0 degree increase in dKH will not result in any noticeable change in your tank either with fish, plants, or algae.  The algae issue was not related to your dKH, more likely ammonia level, excessive light, or it hitchhiked on some plant material you added to the tank (possibly a combination of all three).

Yes, the pH of your re-mineralized water is 'high' but it can easily be lowered. Acetic acid (aka white vinegar) can be used to drop the pH.  Add very small amounts (like 1/8 teaspoon or less) to the 10 gallons of water, mix thoroughly, and re-test the pH.

Personally I would not go through the work or expense of buying distilled water and re-mineralizing.  There was absolutely nothing wrong with the water parameters that you started with.  Keep in mind that the water parameters of our local water supplies vary over the course of the year depending upon the amount of water (rain and snow) that occurs will increase or decrease the concentrations of minerals. 

My 10 gallon 'low tech' tank below, -Roy

Edited February 25, 2022 by Seattle_Aquarist

[SkaleyAquatics]

@Seattle_Aquarist While I agree with you about the original parameters being fine, I was already buying the distilled water and mixing it. I was paying $6/month for 15 gallons, as I am just refilling 5gal jugs at the grocery store. The reason I am mixing is because out of the tap I struggle to grow plants as my parameters are 8ph, 22gh, and 14kh.

[Seattle_Aquarist]

On 2/25/2022 at 8:50 AM, SkaleyAquatics said:

@Seattle_Aquarist While I agree with you about the original parameters being fine, I was already buying the distilled water and mixing it. I was paying $6/month for 15 gallons, as I am just refilling 5gal jugs at the grocery store. The reason I am mixing is because out of the tap I struggle to grow plants as my parameters are 8ph, 22gh, and 14kh.

Hi @SkaleyAquatics

OK, I assumed the 3 dKH and 7 dGH were your tap water, my bad I missed the part were you were mixing tap and distilled.  So try my suggestion with the white vinegar and see if that doesn't drop your pH to a more reasonable level, the cause of the high pH was the CaCO3 (calcium carbonate) which removed H2 ions from the water and increased the pH.  When you order minerals again I suggest trying what I use and that is CaSO4 which will still provide the Ca but not strip the H2 ions.

Obviously plants need many nutrients besides macros (N,P,K) and secondary (Fe, Ca, Mg) but also a host of micro-nutrients (S, B, Mn, Cl, Cu, etc),  What are you using to cover the range of nutrient requirements? -Roy

[SkaleyAquatics]

On 2/25/2022 at 12:19 PM, Seattle_Aquarist said:

Obviously plants need many nutrients besides macros (N,P,K) and secondary (Fe, Ca, Mg) but also a host of micro-nutrients (S, B, Mn, Cl, Cu, etc),  What are you using to cover the range of nutrient requirements? -Roy

Hello @Seattle_Aquarist,

In regards to this, I switched from Aquarium CO-OP Easy Green/Iron/Carbon to APT Complete 3 about 3 weeks ago. I am dosing at 2ml 4x/week. I was going to do EI dosing but time is limited currently and this dosing only takes a few minutes for me.

On 2/25/2022 at 12:19 PM, Seattle_Aquarist said:

OK, I assumed the 3 dKH and 7 dGH were your tap water, my bad I missed the part were you were mixing tap and distilled.  So try my suggestion with the white vinegar and see if that doesn't drop your pH to a more reasonable level, the cause of the high pH was the CaCO3 (calcium carbonate) which removed H2 ions from the water and increased the pH.  When you order minerals again I suggest trying what I use and that is CaSO4 which will still provide the Ca but not strip the H2 ions.

I am actually using CaSO4 already, however if CO3 is the cause of the pH increase then K2CO3, could cause this and appears that is the case. As I asked somewhere else also and someone confirmed that this will cause the pH to spike for ~24hrs. 

Also @Seattle_Aquarist what is the plant in the last picture you provided?

Edited February 25, 2022 by SkaleyAquatics

[Seattle_Aquarist]

Hi @SkaleyAquatics

Yes, the K2CO3 will also increase your pH, missed that one.

The plant in my last post was Pogostemon erectus, it grows well in both high and low tech tanks but needs moderate (like your 7 dGH) to softer water.  -Roy

[Mmiller2001]

I just want to add this tidbit. 

When you work with distilled or RO water, there's no significant amount of acids or bases to influence pH. So while it's in storage, you might see a range of pH's that seems confusing. 

My RO water, with 0 TDS will have a pH near 9. Why? Because of atmospheric influence (O2/CO2). When I dossed K2CO3, my pH would skyrocket. This is not a problem. Once the water is introduced into the tank, it will almost immediately respond to the acids in the tank and test to numbers you would expect to see.

What's important is that GH and KH, between both tank and storage, are similar.

I mix my RO to 4.5dGH and 0dKH. This water will be about 9pH. My aquariums are at 4.85pH and 5.0ph. After my water change, the water will test near the 4.85 and 5.0pH. So don't worry, in this instance, what's important is the relative TDS.

[SkaleyAquatics]

On 2/25/2022 at 2:32 PM, Mmiller2001 said:

I just want to add this tidbit. 

When you work with distilled or RO water, there's no significant amount of acids or bases to influence pH. So while it's in storage, you might see a range of pH's that seems confusing. 

My RO water, with 0 TDS will have a pH near 9. Why? Because of atmospheric influence (O2/CO2). When I dossed K2CO3, my pH would skyrocket. This is not a problem. Once the water is introduced into the tank, it will almost immediately respond to the acids in the tank and test to numbers you would expect to see.

What's important is that GH and KH, between both tank and storage, are similar.

I mix my RO to 4.5dGH and 0dKH. This water will be about 9pH. My aquariums are at 4.85pH and 5.0ph. After my water change, the water will test near the 4.85 and 5.0pH. So don't worry, in this instance, what's important is the relative TDS.

Hello @Mmiller2001

Thanks for this, I will see my numbers on Sunday when I perform my weekly water change. I am glad you chimed in as you were one of my influences for switching to re-mineralizing the water instead of mixing, as was Greggz from TPT. 

[Mmiller2001]

On 2/25/2022 at 12:41 PM, SkaleyAquatics said:

Hello @Mmiller2001

Thanks for this, I will see my numbers on Sunday when I perform my weekly water change. I am glad you chimed in as you were one of my influences for switching to re-mineralizing the water instead of mixing, as was Greggz from TPT. 

Greggz certainly challenges "norms" doesn't he! He's why I went to 0dKH water. 

Did you see his recent post about water change temperature? Lol, that's going to unsettle quite a few people!

[SkaleyAquatics]

On 2/25/2022 at 2:47 PM, Mmiller2001 said:

Greggz certainly challenges "norms" doesn't he! He's why I went to 0dKH water. 

Did you see his recent post about water change temperature? Lol, that's going to unsettle quite a few people!

While I read many of the pages but not all he has debunked some of the common "norms" for sure. The 0dkh and pH drop both being some big ones. 

I have not read through the update  yet. I was posting about this issue and have decided to start my own Journal and have been working on that. I plan to post the journal here as well. 

[SkaleyAquatics]

To update everyone on this, I did check the water Sunday morning as I was gone Saturday and the pH was at 7.3

[Mmiller2001]

On 2/28/2022 at 5:41 PM, SkaleyAquatics said:

To update everyone on this, I did check the water Sunday morning as I was gone Saturday and the pH was at 7.3

Tank water or reserve mineralized water?

[SkaleyAquatics]

On 2/28/2022 at 8:45 PM, Mmiller2001 said:

Tank water or reserve mineralized water?

That was tank water I believe the reserve water was 6.2 but don't qoute me on that