What's making my water hard?

[sepehr]

I don't get it, I use 3/4 RO 1/4 tap water for my weekly water changes. RO has a PH of 7.2 & tap has a PH of 8.0 and the PH of my water comes out to be between 7.4 & 7.6. I have a 12 gallon tank that I apply the same portions of water and it has a PH of 6.8.

Both tank are injected with CO2, I use Red Sea Flora Base which SHOULD maintain the water slightly on the acidic side. I have 2 small pieces of dirft wood. I don't have a stones in my main tank but I use several small stones in my 12 gallon tank and yet it has a lower PH.

The only thing that I could think of is K2SO4. I dose according to EI but I kind of overdose K2SO4 (not a lot though). Is this causing the PH to rise? I'm dumb founded. Does anyone have any idea whats happening here?

[happi]

are you dosing any Ca or Mg?

[sepehr]

Originally Posted by happi

are you dosing any Ca or Mg?

No, I don't since I add 5 gallons of tap (1/4 of the new water) to my tank as part of the water change. And believe me the tap water here is rock hard. Eventhough it's a small portion but that's what I count on for Ca & the Mg. Some people say that's not enough and I should go with 50-50 mix but my PH is high as it as rightnow with 3/4 RO & 1/4 tap...so what gives? there must be something in the tank but I nothing crosses my mind...strange

[mattycakesclark]

Many things affect pH, not just RO/tap mix and mineral content.

Do you need the pH of the water lower for some sort of livestock?

[happi]

Originally Posted by sepehr

No, I don't since I add 5 gallons of tap (1/4 of the new water) to my tank as part of the water change. And believe me the tap water here is rock hard. Eventhough it's a small portion but that's what I count on for Ca & the Mg. Some people say that's not enough and I should go with 50-50 mix but my PH is high as it as rightnow with 3/4 RO & 1/4 tap...so what gives? there must be something in the tank but I nothing crosses my mind...strange

how can you be sure about how much Mg your tap water have? Tap water could have high GH and PH and have 0 Mg while having high Ca only.


add K2so4 during water change only, you will provide enough K2so4 through KNO3.

start using more of RO water and add less of tap water.

[sepehr]

Originally Posted by happi

how can you be sure about how much Mg your tap water have? Tap water could have high GH and PH and have 0 Mg while having high Ca only.


add K2so4 during water change only, you will provide enough K2so4 through KNO3.

start using more of RO water and add less of tap water.

That's true but do you know if the sulfate part k2so4 makes the PH rise if dosed more than normal? And yes this weekend I'm going to use RO only to see if it makes any difference.

[sepehr]

Originally Posted by mattycakesclark

Many things affect pH, not just RO/tap mix and mineral content.

Do you need the pH of the water lower for some sort of livestock?

I got rummy noses, cardinals, and ottos. I know that most fish & plants can handle a PH from 6.5 to 8.5 as long as the KH is steady. But I'm curious why my PH isnt lower. I inject CO2, got acidic substrate so it would only makes sense that the PH should be lower than what it actually is rightnow.

In the upcoming wc I'm going to use RO only, up the CO2 bps, and dose less k2so4. Lets see it it makes any difference.

[happi]

Originally Posted by sepehr

That's true but do you know if the sulfate part k2so4 makes the PH rise if dosed more than normal? And yes this weekend I'm going to use RO only to see if it makes any difference.

its possible that K2SO4 could raise the GH slightly but i have not came across with any big change in GH due to that. however every time you add the ferts you will see increase in the tds, if testing with tds meter you will get results like 250ppm of tds while testing with api it might read only 200 tds. 200ppm of tds is the correct GH. am not sure how you are testing your stuff? i tested my PH and it always read 6.0 during the day when co2 is on.

according to tds meter the GH is reading 270ppm on my tank right now. i have not tested it with the api kit yet, but am sure its around 7-8dgh.

[happi]

Originally Posted by sepehr

I got rummy noses, cardinals, and ottos. I know that most fish & plants can handle a PH from 6.5 to 8.5 as long as the KH is steady. But I'm curious why my PH isnt lower. I inject CO2, got acidic substrate so it would only makes sense that the PH should be lower than what it actually is rightnow.

In the upcoming wc I'm going to use RO only, up the CO2 bps, and dose less k2so4. Lets see it it makes any difference.

don't forget to increase the KH with baking soda if you are going to use RO only. i dose 2tsp in my 50g during water change, which gives 1-2dgh.