Water ph help

BENT17
Member
Hi all. I need your expertise here.. so I have an Ro which is stage 5 with a mineralizer with kh2 and GH2. I went to buy a mineralizer to incerase minerals in my RO reservoir which I keep for water changes (100L) I took reading before I added the minerals in the reservoir and noticed something strange.. TDS in aquarium is 170 and in RO tank is 55, but when I tested the PH as you can see in the photo are two opposites the Dark blue is the RO reservoir and the other one is my aquarium water one day after WC using the RO reservoir water.. The minerals I bought increases PH which will end up increasing My PH much more.. not sure what to do here.. any experts?
 
jtjgg
Member
KH is carbonate which is directly proportional to pH. more KH higher pH.

is this for Discus or South American tank?

what is the pH of the tap, the RO water and the tank?
what is the KH of the tap, RO, and the tank?
 
  • Thread Starter
BENT17
Member
So I did some tests and I have two RO reserve tanks in my balcony which are giving high PH results. This is coming from RO with mineralizer. The other test is from same RO WITHOUT mineralizer. (Photos attached) second photo is PH GH and KH from RO without mineralizer.. I think best way forward is removing completely the mineralizer from the equation an dose minerals manually.. oh yeah also - PH in tank (which comes from the high PH reservoir tanks is around 6.4-6.5
Eliminated the mineralizer. It had water passing these minerals..
 
MacZ
Member
Do everybody a favour and DON'T post pictures of the test vials. Just give the readings. Pictures (especially without the chart next to the vials) are useless. Or at least name the pictures correspondently.

TDS is not directly corresponding to pH. So any results on TDS (are you talking µSI or ppm, btw?) do not have any explanatory value for pH. So leave those out. It's normal that they are higher in the actual tank, as you said there is soil in it and TDS meters measure EVERYTHING solved in the water. I mean, it stands for TOTAL DISSOLVED SOLIDS.
For your purposes a TDS meter is all but useful. Those things are a must have for setups that need to have extremely low hardness/pH, like breeding softwater fish or full-on blackwater. The only use I see for you is testing whether the membrane of your RO unit is still working.

So you have two reserve tanks with remineralised RO. Well, as soon as you mineralise it, it is not RO anymore, but remineralised water. And with a measurableable KH, this leads to a higher pH.

As for the pH in the aquarium: You said you are using soil, right? That lowers pH temporarily significantly when using RO or low-KH water.

I don't get what you want, honestly. All is as expected.

----------------------------------------------
Here the basics:
pH, KH and CO2 are connected.

Carbonate + 2H+ <-> Hydrogencarbonate + H+ <-> carbonic acid <-> CO2/H2O
(The "<->" means that these reactions are in flux and constantly balancing out.)

pH: H+ are Hydronium ions, which are measured in pH. The more H+, the more acidic, the lower the pH.
KH (Karbonathärte = german for carbonate hardness) is the measurement of carbonates in the water, the more carbonates the higher the KH, the more H+ is bound to carbonates, the higher the pH.

RO has no KH, so the pH may go as low as 5 just due to gas exchange with the air at the surface. The CO2 gasses off over time, bringing the pH to around neutral at 6.8-7.2.
----------------------------------------------

jtjgg said:
is this for Discus or South American tank?
OP is trying to do a high-tech planted tank.
 
  • Thread Starter
BENT17
Member
First off sorry about the photos of the results I'm new here so didnt know..

I Have 2x 100L tanks with RO water which passes through the mineralizer which is used for WC. Kh and gh are both at 2 but PH is at its highest level (7.5/7.6). I Tested out the RO without mineralizer and they are both kh and gh at 1 and PH is 6.5. My reservoirs have no soil inside just a plastic tanks. Aquarium has substrate which lowers my PH as from a 7.6 PH from the reservoir to the tank drops to 6.4

Tank is a high tech one with CO2 and I have shrimps and tetras so far.

My question is.. should I eliminate the mineralizer and mineralize manually or keep the mineralizer and keep all as it is?
 
MacZ
Member
Yeah, I got all of this, you're not telling me anything new. Hasn't got to do anything with being new, it's just common sense.

BENT17 said:
I Have 2x 100L tanks with RO water which passes through the mineralizer which is used for WC. Kh and gh are both at 2 but PH is at its highest level (7.5/7.6).
As expected. This is not RO anymore. It's just remineralised water. And the pH is as expected for a KH of 2.

BENT17 said:
Tested out the RO without mineralizer and they are both kh and gh at 1 and PH is 6.5.
As expected, the pH is due to CO2 from the air. Also, KH and GH at 1 stop the CO2 from lowering the pH beyond 6.5. These readings for KH and GH in RO means your membrane has to be replaced.

BENT17 said:
My reservoirs have no soil inside just a plastic tanks.
You are aware that "tank" and "aquarium" are synonymous in English? When I wrote you have soil in your tank, I was referring to the aquarium.

BENT17 said:
Aquarium has substrate which lowers my PH as from a 7.6 PH from the reservoir to the tank drops to 6.4
I know, that's what I was referring to.

BENT17 said:
My question is.. should I eliminate the mineralizer and mineralize manually or keep the mineralizer and keep all as it is?
Remineralise yourself. Obviously the system is taking away control from you and you should be in control for this.
 
  • Thread Starter
BENT17
Member
Thanks for your replies. So I will remove the mineralizer and dose myself.

Would you get rid of the 200L mineralized water of can I use it for my other two water changes?

This is the mineralizer I got. Has anyone ever used this?
 
MacZ
Member
BENT17 said:
Would you get rid of the 200L mineralized water of can I use it for my other two water changes?
Do whatever you see fit, but this will only extend the situation

BENT17 said:
This is the mineralizer I got. Has anyone ever used this?
This is not what you need. This is just adding carbonates.

Ask separately for a recommendation for planted tanks.
 
  • Thread Starter
BENT17
Member
Thanks will do!
MacZ said:
As expected, the pH is due to CO2 from the air. Also, KH and GH at 1 stop the CO2 from lowering the pH beyond 6.5. These readings for KH and GH in RO means your membrane has to be replaced.
What do you mean "The pH is due to CO2 from the air?
Since the water is in a tank the pH increases?

Also after eliminating the mineralizer, do I still need to replace the membrane?

Thanks for all your help
 
MacZ
Member
BENT17 said:
What do you mean "The pH is due to CO2 from the air?
Since the water is in a tank the pH increases?
RO fresh from the RO unit takes up CO2 from the air, lowering pH usually down to 5. When you let it sit for a while the concentration of CO2 in the water gets to an equilibrium, ending in a higher pH. As it still has KH, the pH doesn't get as low and so 6.5 is the lowest it can go.

BENT17 said:
Also after eliminating the mineralizer, do I still need to replace the membrane?
As the RO unit puts out water with detectable GH and KH, the membrane is probably due for replacement.
Is your tap water very hard? Another reason could be using warm tap water.
 
  • Thread Starter
BENT17
Member
Understood thanks will change the membrane then to get kh and gh down to zero.. yes my tap water is crazy high thats why I had to go for RO water. With regards the reservoir should I place in a circulating pump and run it 24/7 or can I leave it as it is. I usually do water change on Fridays and its filled back up Saturday evening. Prior to the water change Input on the heater in the tank and circulate the water for an even temperature reading
 
MacZ
Member
BENT17 said:
Understood thanks will change the membrane then to get kh and gh down to zero.. yes my tap water is crazy high thats why I had to go for RO water.
Yeah, depnding on the hardness readings even a new membrane might not help. But the higher the hardness the shorter tha lifetime of a membrane. You might eventually want to replace one of the stages after the membrane just with a second membrane.

BENT17 said:
With regards the reservoir should I place in a circulating pump and run it 24/7 or can I leave it as it is. I usually do water change on Fridays and its filled back up Saturday evening. Prior to the water change Input on the heater in the tank and circulate the water for an even temperature reading
An air pump would be enough, but in principle it's enough to let it sit over night.

And remember when remineralising manually that you mix in the reservoir. So maybe a pump for circulation might be a good idea after all.
 
  • Thread Starter
BENT17
Member
MacZ said:
Yeah, depnding on the hardness readings even a new membrane might not help. But the higher the hardness the shorter tha lifetime of a membrane. You might eventually want to replace one of the stages after the membrane just with a second membrane.



An air pump would be enough, but in principle it's enough to let it sit over night.

And remember when remineralising manually that you mix in the reservoir. So maybe a pump for circulation might be a good idea after all.
In fact I was trying to figure out why having two tanks with the same water and one tank had a higher PH than the other one, makes perfect sense then!

I was thinking of adding minerals a few hrs before waterchange and leaving the pump on. (Only reason is not to have the pump on for 247 for a whole week on thats all but if it helps then ill leave it on..
 
MacZ
Member
BENT17 said:
I was thinking of adding minerals a few hrs before waterchange and leaving the pump on. (Only reason is not to have the pump on for 247 for a whole week on thats all but if it helps then ill leave it on..
I did not imply to leave it on 24/7, just turn it on the night before a waterchange so the minerals are definitely dissolved and the CO2 is driven out, so the water is least altered before use.
 
  • Thread Starter
BENT17
Member
Thankd for your help! Now just hoping someone gets back to me on the other post on which minerals I need to use
 

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