H20 To Ro

[smitt_graham]

I started my tank 240ltr with normal tap water and want to change it to RO for the low ph. I started with tap water just for it being easier filling my tank ( hose pipe ) I was just wondering how long it will take for the ph to drop. Every water change im putting RO only back in tank min of 50ltrs. I am on my third change. It has dropped a bit down to about 7.0 - 7.5 any one any ideas. I am putting minerals in to the ro.
Cheers smitt_graham

 

[rabbut]

Whats your starting pH and target? The pH of the RO you are adding also needs to be known to wrok this out

All the best
Rabbut

 

[smithrc]

Dont do any more RO changes.... its not just the PH you will be affecting - you will be removing all the buffering eleaments from the tank also making for a very unstable tank - that will be lethal to its inhabitants...

RO for ever day use should be buffered and minerals added back in before use....

Wander over to the marine section and have a read round there - the same theory applies for freshwater

 

[smitt_graham]

Dont do any more RO changes.... its not just the PH you will be affecting - you will be removing all the buffering eleaments from the tank also making for a very unstable tank - that will be lethal to its inhabitants...

RO for ever day use should be buffered and minerals added back in before use....

Wander over to the marine section and have a read round there - the same theory applies for freshwater

Im only doing weekly changes as normal and adding the minerals is this still not good then. What is the difference of doing weekly changes with tap water ? Im not sure i understand

 

[SJ2K]

Why do you want your Ph lower then that? 7-7.5 is perfect and changing to RO for a FW tank will just cause more problems.

 

[smitt_graham]

Why do you want your Ph lower then that? 7-7.5 is perfect and changing to RO for a FW tank will just cause more problems.

My tap water is 8.0ph so should i do a 60/40 RO/TAP WATER weekly change and just keep checking the ph. Would this be ok

 

[rabbut]

The way to work out the ratio of RO to tap water to use, is complicated, as the pH scale is logarithmic. This means that the pH will not chage at a constant rate of the ammount of electrolites that you add to up the pH.
As a very rugh guess, you could aim with the values above, to do a 50/50 split, in a bucket, and then check the pH. It will probibly need more RO, but in this section of the scale, you wouldn't be far off. If you are mixing with tap water, there is not need for minerals to be added, as you are diluting down those in tap water to get your pH right. If you are using pure RO, you will need to add minerals.
It is genera;y considered easier to get fish to match the pH of your tap water, than it is to try changing the pH. I asy this as diluting down the minerals in the water will make the pH less stable, and thus more likely to swing. Most mineral products will only raise your pH to about 2oG of hardness, which isn't alot. If CO2 built up in water of that hardness, or nitrates/nitrites for that matter, the pH maight crash

All the best
Rabbut