# Water Hardness vs. CO2 diffusion



## Tom (16 Sep 2011)

Our water is seriously hard. I'm struggling to get enough CO2 dissolved in the Mini M (pushing 2bps), and was wondering how much difference there would be if I cut it 50/50 with RO when I start the 60P. Has anyone looked into how hard it is to achieve a set CO2 concentration in different levels of hardness?

Tom


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## George Farmer (16 Sep 2011)

I haven't tested it properly but since cutting my tap with RO my plants pearl a lot more. Same light, same nutrients, same circulation, same CO2 bubble rate.

Whether or not it is CO2 related, I don't know.


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## Aquadream (16 Sep 2011)

When I use to live in Hemel Hempstead I measured the water there and it was out of the scale, so hard. Then i started using RO to mix in ratio RO 75% to tap water 25%. It seem to be good enough. Plants were growing well.


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## dafil (16 Sep 2011)

Tom said:
			
		

> Our water is seriously hard. I'm struggling to get enough CO2 dissolved in the Mini M (pushing 2bps), and was wondering how much difference there would be if I cut it 50/50 with RO when I start the 60P. Has anyone looked into how hard it is to achieve a set CO2 concentration in different levels of hardness?
> 
> Tom


Hi,Tom,
with soft water you will have lower Ph.CO2 concentration will be the same.



			
				George Farmer said:
			
		

> I haven't tested it properly but since cutting my tap with RO my plants pearl a lot more. Same light, same nutrients, same circulation, same CO2 bubble rate.
> 
> Whether or not it is CO2 related, I don't know.



May be plants lprefer a little acidic water...


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## Tom (16 Sep 2011)

dafil said:
			
		

> Hi,Tom,
> with soft water you will have lower Ph.CO2 concentration will be the same.



Yes I realise this, however it is more difficult to dissolve CO2 in harder water. That is what I was asking, if anyone knows more details as to the correlation.


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## dafil (16 Sep 2011)

May be your  wright question must be"why   it is more difficult to lower Ph in hard water"
If you reach 30ppm CO2 with 2bps in hard water,you will reach the same concentracion with the same bps in soft water.Only the Ph readings will be diferent.
 do you use a drop checker/4dKh/


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## Tom (16 Sep 2011)

Surely it's more difficult to lower pH in hard water due to more buffers being present. Does that have anything to do with CO2?

If I reach 30ppm @2bps in hard water, I would expect to be able to reach the same ppm with less bps in soft water would I not? Assuming diffusion methods are the same.


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## dafil (16 Sep 2011)

If you use a drop checker with 4dKh solution/NOT with aquarium water/,you will see that there will be not difference!!!


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## Garuf (17 Sep 2011)

I suspect the intensification in pearling is down to the carrying capacity of water rather than any increase in health? Lower ph's can absorb more co2 into the water but if the bubble count hasn't changed the change in itself should be minimal. Maybe it's simply that the o2 is having a harder time to dissolve and is causing a fake pearling type effect or the water is becoming more saturated more quickly? I'm clutch at straws slightly as I don't know enough on the carrying capacity of gases in water, but I think it's likely to be placebo unless the plants are those associated with waters of a very low gh? I await Tom or Ceg's imput on this as it's something I often wonder about with my Leeds and Stoke water being at opposite ends of the scale.


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## Tom (23 Sep 2011)

Tom or Clive, you there? lol

This last week I've been getting a lot of Staghorn (every plant and rock surface) and a bit of BBA. My CO2 has been at 3bps for about a week, and this is in a 25liter tank. Surely that is mad? The bubbles are getting hit first by a powerhead, then moved into the path of the Eheim Pro300 outlet. I've tried using my inline diffuser again, but I can't get the tubing to stay on. It just bursts off and water flies everywhere. 

I've just moved down to an 11w from an 18w to see if it makes any difference (I used to use a 24w at 1bps CO2 with absolutely no problems.)


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