Changing Kh

[alex1]

I have just set up a system to collect rain water and intend to use it partaily in my tank.
The KH of my tap water is 14-15 so I have to use a lot of Co2 to get the PH down and a decent level of co2.
What level of KH should I aim for and how quickly can I lower it?
I presumed it is better to go slowly, what level of KH should I aim for and has anyone any idea how much rain water to add to the tap water?

 

[kamel_007]

I have just set up a system to collect rain water and intend to use it partaily in my tank.
The KH of my tap water is 14-15 so I have to use a lot of Co2 to get the PH down and a decent level of co2.
What level of KH should I aim for and how quickly can I lower it?
I presumed it is better to go slowly, what level of KH should I aim for and has anyone any idea how much rain water to add to the tap water?

Well, Ro water is more reliable.

But no pro with Rain water, you have to boil it before you add it, to kill germs..etc

test the rain water KH, PH, this the important things.

get a container, to make the test, to decide the rain water rate to tap water,,

For Example :

Add 800 Ml from rain water to 200 ML from tap water, then test the KH,Ph...

Good Luck

 

[George Farmer]

Rain has zero KH so adding it to your tap will reduce the tap’s KH directly proportionally i.e. a 50:50 mix of rain/tap will give you a final KH of 7-7.5.

I have no personal experience using rain but assume it is safe as long as you don’t live in a heavily industrialised area and it is stored in a food safe container.

I know at least one experienced aquarist who swears by using (untreated) rainwater mixed with tap.

 

[pieman]

Make sure your not using acid rain

 

[alex1]

How do you recognise acid rain?

 

[alex1]

Just answered my own question -(googled).
Found out that rain water has a 'normal' ph of between 5.6-5.7, mine measures at about 6 so I guess I do not have acid rain.
Many other points raised, such as the dissolved contaminants in rain are probably less than those found in tap water. Has anyone got any views on this?

 

[qwikimpss]

Test the PH, acid rain is acidic....thats about it really.

 

[Themuleous]

Hi pied piper

I’ve never used it personally but from what I've read in PFK mag (not the plant articles George! ) Generally you are fine with rain water, provided it is 'clean' when you add it to the tank I.e. it doesn't collect moss and other debris when it lands on whatever you collect it from.

The whole contamination thing is only really important if you live in a chemical factory that pumps toxic gases directly into the rain your collecting i.e it shouldn’t be a problem!

If you're in any doubt you can always run in through a carbon filter before you add it to you aquarium that should remove any nasties.

Word of warning, as George said it'll be KH 0 so you'd probably be needing to add some sort of additive to it or add tap water to get the right KH and GH, plus this should get your pH up, 6ish is generally fine but you may want to think about getting it more like 6.5. Any thoughts on this anyone else, Im not really sure if that’s correct?

Hope this helps

Sam

 

[alex1]

The PH in my tank is generally on the high end unless I add loads of Co2 ( 7.6 - 7.8 without co2) , so I am hoping that the rain water will reduce my need for co2 - I am going through a bottle a month at the moment!
I intend to start with the rain water tommorrow, to gradually reduce my KH - anyone with advice as to what is a good level of KH to aim for?

 

[George Farmer]

CO2 is CO2. KH has no bearing on how much you need to add. 30ppm stable is the ideal target.

A KH anywhere between 3 and 10 is ideal. Most plants aren't fussy providing there's enough light, CO2 and other nutrients.

 

[alex1]

I have obviously totally missed the plot with my co2, I thought that the Ph and KH together( using one of those calculators) gave you the reading of how much co2 was in the tank.
Can you let me know how to correctly calculate the co2 level in my tank, before I do some real damage?
Why do I need to use so much co2 then? It is probably that I am because I am doing something wrong in my calculations.

Heeeeeeeeeelp!

 

[zig]

The problem is that if you change your KH you also change your Ph.

Read about it HERE

If you lower your KH your Ph will lower alongside it, and vice versa if you raise your KH your Ph will also rise.

 

[alex1]

Thanks for the help, just one thing why oh why am I using so much co2 - my bottle has just run out again - this time it only lasted just over 3 weeks.
I aim to keep my ph at 7.2 with my KH being at 16 it sems to take so many bubbles just to keep the ph from rising to over 7.8. We have checked for leaks in the system and cannot find any --

 

[zig]

I dont know how big your tank is or how big the CO2 cylinder is, a rough benchmark for pressurised CO2 injection would be 1 bubble per second for a 40 US gallon tank and this should get you into the ballpark of 30ppm CO2, presumeing off course the diffusion method that you use is efficient.

 

[alex1]

My tank is 160l and I was using a 500g co2 tank, I have now changed it to a 1000g yesterday when I went in to get it refilled.
There must be something wrong somewhere in my system as reading other threads , people say their co2 tanks last over 3 months!