lowering ph with RO/DI water

[flitabout]

I want to lower my ph using a mix of RO and DI water. I have what has been called liquid rock. My Ph in the tank is 8.6-8.8. The RO water I bought tests at 6.4-6.6 I haven't tested the DI yet. I am doing my weekly water change tomorrow and I don't want to totally stress out my fish. When I did the change last week my tap was testing 8.8 maybe higher but that is as high as my test goes. I did a 50% change on a 37g using 2g of DI, 4g of RO and the rest in tap. It brought the tank to 8.6.
This week I have 10 gallons of DI and 6g of RO to use. What is the best mix so I don't stress the fish while still getting the PH lower and stable? Buffering isn't an issue my tap has a tun. I did an experiement in an aerated 5 gallon bucket where I added a 1/4 cup of vinegar every day for a week and only got the ph down to 8.2 I left it go fo 1 day without adding vinegar to see if it was stable and it shot right back up to 8.8 Any ideas? I think my hubby will kill me when he comes home and sees 16g jugs of water! So I would like to do my water change today before he gets home so I can hide the jugs!

 

[flitabout]

Anybody???

 

[molliwopp]

If you tap is ph8.6 and the water you have is ph6.6 the 50/50 ro to tap should bring it to 7.6 if im doing the calculation right.

Hasnt the ro been deironised?

 

[flitabout]

Not sure it says ozonated to enure quality Oh what that's on the DI. My fert has iron so I'm not worried about that.

 

[molliwopp]

Not sure it says ozonated to enure quality Oh what that's on the DI. My fert has iron so I'm not worried about that.

Im just alittle stumped as most ro water you buy at the lfs comes deironised, here in the uk anyway. So im wondering why you have 2 different waters, one di and one ro. Incase you didnt know DI means deironised. You probably knew that and ive just insulted your intelligence.

 

[Darkseid76]

If you truly don't want to stress your fish then leave the PH alone.

 

[molliwopp]

If you truly don't want to stress your fish then leave the PH alone.

Correctly mixing ro can be done safely and productively. Most fish can adjust to ph but 8.6 is rather high and could cause stress in itself. OP What fish do you have?

 

[flitabout]

Swordtail fry, platy fry, a platy and cardinal tetras. I just did my weekly change and I did 13g of RO and DI water and about 4g of tap water and it seems to have brought the tank down to about 7.4. I am going to give it some time to off gas and test again in a few hours. My ph seems to rise as it aerates 4 hours is about the norm for that s well see what it is around 4pm this afternoon for an actually number once the buffers go wacko.

 

[molliwopp]

You need to keep the ro/tap mix the same everytime you change any water to stop ph swings.

Do some small tests. 50/50 is exactly that no matter how much or how little water you use.

Fill half a glass with ro and half tap and test.
250ml tap and 250ml ro is the exactly the same as 25gallons tap 25gallons ro.

Are you aiming for a specific ph or just wanting to lower it?

 

[Scottyhorse]

8.6 to 7.4 is too far of a jump IMO. Try going like this each water change:
8.6 -
8.2-
7.8-
So going down .4 PPM each time. You could do 2-3 water changes each week to make it go a little faster. But a PH of 7.8 would be a good place for your mix of fish.

 

[flitabout]

I just want to get it around 8. I was upping the ratio because of the water already in the tank. I am also going to start testing the straight tap every couple of weeks because of the huge jump in the last month to 6 weeks. I started off around the first of August with levels of
Ammo 0
Nitrite 0
Nitrate 0
PH 7.4-7.6
To
Ammo .5
Nitrite 0
Nitrate 5-10
PH 8.6-8.8
So it's really hard to get the levels stable with the tap being so unstable. I am having to constantly readjust to keep it that way. I have been considering dumping all of the water and going with straight RO water and using crushed coral for buffering. I just keep thinking it shouldn't be this hard...

 

[Rivercats]

When you have unstable tap water that varies that much going to straight RO and remineralizing it is actually the best thing to do. I have a portable RO unit that I thought was very reasonably priced and have been using it for over 2 years. All you need are jugs to store water in when you make it. I have 8- 2 gallon jugs I use. This is the unit I have, the Pro-100.... portable countertop reverse osmosis drinking water system - remove fluoride, chemicals, pharmaceuticals, prescription drugs and more

 

[flitabout]

Well after my day I guess I can go straight to RO water!!!!! Holy crap what a day!

 

[Rivercats]

I use a percentage of RO in all my tanks and in the past have done straight RO with remineralizing. At least that way you can get the exact levels you want. You just have to be consistent weekly on how you use it.