# CO2 in a hard water tank?



## mjw1476 (19 May 2009)

i recently visited a brach of MA and to my surprise was baffled by the knowledge of one guy about the chemistry behind tank water.

from what i could accertain, he said that as Kent tap water is very hard the CO2 im pumping in my tank through a pressurised system is being changed by the high KH into cardon oxide? which isnt being taken up by my plants and will cause them to use all of the stored starch used for growth over around a year at which point the plans will in effect 'burn out' and stop growing! could someone help as ive just had a rather large outbreak of algae which im starting to get to stop growing and looking art avenues to rid me of the smaller bits such as excel and SAEs.

could anyone shed some light on this and whether the advice i recieved is right? the guy sounded very clued up but its such a chore to keep filtering of RO, which is the main reason i got rid of my discus!

is there any way around it? ive increased my flow around the tank which was lacking and cut down on the lights to 6 hours to prevent the algae getting any more out of hand!!

thanks for your help, i hope someone will know it in this sort of depth, clive?

cheers

Matt


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## a1Matt (19 May 2009)

No need for RO for CO2 injection.  KH is not a big deal in this respect.  It seems like the guy in the LFS is discussing how the level of KH may affect the solubility of CO2 in the water.  It is a valid discussion but more for those into their in depth water chemistry, you can ignore it and still grow plants OK.

The basic principles are:

light primarily drives growth, which effectively determines CO2 requirements -> then add enough CO2 which determines fert requirements -> then add enough macros (and then micros).

So.... Yes, adding CO2 causes the plants to use up their stores, but only if you are not dosing enough ferts. 

Hope that helps.  Clive or James could no doubt shed more detailed light on the chemistry, but I think you would be better off not knowing at this stage! ( .... although if you do want to know a bit more, look here: http://www.barrreport.com/co2-aquatic-p ... on-kh.html )

Better to concentrate on getting shot of that algae first  

A good first step to that is identifying what algae you have.  There are different types which have different causes.  James planted tank website is a good starting point for that: http://www.theplantedtank.co.uk/algae.htm

Then post back with the algae type, and the spec of your tank (lights, filter tank size etc) and we can take it from there...


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## a1Matt (19 May 2009)

By the way, I live in Kent with hard water out of the tap as well!   Had no problem with injected CO2 of course


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## mjw1476 (19 May 2009)

lovely, thanks for that matt that puts my mind at rest!

well my spray bar was disconnected slightly to the filter as it slipped off the connection so flow was reduced for around 4-5 days i think! the algae ive got it hair algae all over the hairgrass but the cherries seem to be all over it so hopefully that, twinned with smaller lighting period will solve any problems, ive got the dosing sorted out now after forgetting a few times over thelast few weeks which probably contributed quite a bit! 

do you dechlorinate or just leave the water to stand? my fish seem fine without dechlorinator as ive only got 25 cardinals and a couple of endlers in a 180l. im going to get a koralia 2 to really increase the flow of the tank as i understand this is a major cause of this type of algae. i really dont want to strip it down again if possible so hopefully i can cap the algae growth now and start killing it off by out competing with the plants. the thing is im going for an iwagumi layout after having a jungle set up and ill be honest, its a completely different ball game!!

thanks again!

Matt


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## mi5haha (19 May 2009)

We have 27 German degree hardness water here. I am injecting Co2 into such water for four years, and plants are still alive. The problem is that the PH is more 8.3 even injecting Co2, so this may leave an unsolved issue. There is a theory saying that plants may not be able to absorb mist Co2 (in comparison with 100% solved) in such PH value. It must be under PH 7.0. Otherwise it would be harmful to plants. 

However, I tried mist Co2 for nearly a month in such 27 German degree hard water, with PH8.3, plants still are pearling in the first hour when the light is on, and they grow well. So I am still going on to see what will be happening in the near future.


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## a1Matt (19 May 2009)

mjw1476 said:
			
		

> lovely, thanks for that matt that puts my mind at rest!



Your more than welcome 



			
				mjw1476 said:
			
		

> well my spray bar was disconnected slightly to the filter as it slipped off the connection so flow was reduced for around 4-5 days i think! the algae ive got it hair algae all over the hairgrass but the cherries seem to be all over it so hopefully that, twinned with smaller lighting period will solve any problems, ive got the dosing sorted out now after forgetting a few times over thelast few weeks which probably contributed quite a bit!



Brill - Sounds to me like you are already on top of things and just time to play the waiting game while things come back to normal. I find an iwagumi layout easier to maintian - as they usually have less plant mass and less obstructions to the flow.



			
				mjw1476 said:
			
		

> do you dechlorinate or just leave the water to stand? my fish seem fine without dechlorinator


If the water company uses chlorine you can let it stand and the chlorine will degas.
If they use chloramine then you need to use dechlor as no matter how long you let it stand it does not go away.

If you are getting on fine already then you are OK. BUT! there is no guarantee the company won't switch to chloramine at some point.  I got a water report and it did not say what they use    so I have always used dechlor just to be on the safe side.  If you buy pond dechlor it works out a lot cheaper. (I dose it with a pipette to aid measurement in increments of ml)




			
				mi5haha said:
			
		

> We have 27 German degree hardness water here. I am injecting Co2 into such water for four years, and plants are still alive. The problem is that the PH is more 8.3 even injecting Co2, so this may leave an unsolved issue. There is a theory saying that plants may not be able to absorb mist Co2 (in comparison with 100% solved) in such PH value. It must be under PH 7.0. Otherwise it would be harmful to plants.
> 
> However, I tried mist Co2 for nearly a month in such 27 German degree hard water, with PH8.3, plants still are pearling in the first hour when the light is on, and they grow well. So I am still going on to see what will be happening in the near future.



Wow! That is very hard water you have in Germany.  My 'hard' UK water is only about 12dGH and 12KH (I think my PH before CO2 is the same as yours with CO2).  I am glad to hear your CO2 injection is still successful


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## mi5haha (19 May 2009)

Wow! That is very hard water you have in Germany. My 'hard' UK water is only about 12dGH and 12KH (I think my PH before CO2 is the same as yours with CO2). I am glad to hear your CO2 injection is still successful 

I am from northern China. I mean 27 degrees GH (German hardness). Sorry for not making myself clear. The advantage of hard water seems to grow red color plants.


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## a1Matt (19 May 2009)

My mistake, you never said you were in Germany. Sorry about that.  It is nice to see poeple from all around the world here on the forum   

I am curious what in hard water could make it easier to grow red plants.
I assume (and I am only making a semi-educated guess here) that it is something that could always be added separately. 
For instance, GH is made up of either calcium or Magnesium (or a combination of both).  When my GH drops I dose Magnesium and Calcium and my plants clearly do better with it.


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## ceg4048 (19 May 2009)

Yes, I agree 100% with a1Matt's assessment. Not only is hard water not an issue but plants don't care one way or another about the pH of the water. It's completely irrelevant. The ph that matter to both aquatic plants and aquatic animals is the INTERNAL pH, not the external one. The mechanism plants use to control their internal pH is the movement of charged particles across their cell boundaries. This is facilitated by the use of metal ions such as Mg and K, ironically, components that hard water usually has in abundance.

The LFS contention that hard water makes it more difficult for plants to uptake carbon is at best, ludicrous. This illusion is generated by the fact that hard water is generally high in pH and the carbonates/bicarbonates in the water act as a buffer to neutralize the small amounts of carbonic acid produced by CO2 dissolving in water. When identical amounts of CO2 are dissolved in hard water the pH drop is not as much as when dissolved in soft water so it _appears_ as if the CO2 is less effective in hard water. While there is some minor differences in the solubility of CO2 between hard and soft, those differences have no effect for our purposes.

Another reason for this illusion is that many of our plants are found in soft acidic natural habitats so that many automatically assume that soft acidic waters are a requirement for plant growth. This is not the case. There are only a handful of plants that require soft water. The vast majority excel in hard water.

I would caution against listening to the advice of that particular LFS as the evidence indicates that they are simply regurgitating misinformation typical programmed by The Matrix...

Cheers,


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## mjw1476 (19 May 2009)

thanks for clearing that up! ill just crack on now with trying to rid myself of this algal bloom! worked out its poor circulation of the co2 and inbalances from a few weeks ago. going to get some excel to try and kill some!

as its taken hold now will it ever go with a crew of 20+ cherry shrimp, 3 large amanos, 2 otos. and im trying to get hold of some true siamese algae eaters, dont want to get the wrong ones and them sit in the corner doing nothing!

is there any way of getting tiny little filaments of algae off of hair grass?

cheers

Matt


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## TDI-line (19 May 2009)

ceg4048 said:
			
		

> I would caution against listening to the advice of that particular LFS as the evidence indicates that they are simply regurgitating misinformation typical programmed by The Matrix...



Next they will be trying to sell you some Rowaphos to remove Phosphate.


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## a1Matt (19 May 2009)

mjw1476 said:
			
		

> thanks for clearing that up! ill just crack on now with trying to rid myself of this algal bloom! worked out its poor circulation of the co2 and inbalances from a few weeks ago. going to get some excel to try and kill some!
> 
> as its taken hold now will it ever go with a crew of 20+ cherry shrimp, 3 large amanos, 2 otos. and im trying to get hold of some true siamese algae eaters, dont want to get the wrong ones and them sit in the corner doing nothing!
> 
> ...



There is a good chance the SAE's will eat it (when I had them amano shrimp and otos there was no algae that was left uneaten).

Main thing is to correct the problem, then sooner or later everything falls into place.  If the clean up crew do not sort it you can wait until you have a month or two of good growth and then trim off any algae infected leafs that may be left.


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## a1Matt (19 May 2009)

TDI-line said:
			
		

> ceg4048 said:
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 I still see Rowaphos on shelves and it makes me cringe. Luckily I have never seen anyone buy it or I would be tempted to stand inbetween them and the till   .


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## TDI-line (19 May 2009)

a1Matt said:
			
		

> TDI-line said:
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Back in the day, i used to spend about Â£35 every two months for the big pot as _i was advised plants and phosphate don't  go well together_. Shoot me down.


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## Ed Seeley (19 May 2009)

I also wouldn't listen to anyone that says the carbon exists as 'carbon oxide' in the water as this term simply isn't used as it's riddled with inaccuracies.  The compounds are Carbon dioxide with 2 oxygen atoms and Carbon monoxide with 1.  The fact that Carbon monoxide isn't very stable in a well oxygenated situation and the stability of Carbon dioxide means that it can't just change into another oxide because the water's hard!!!


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## ceg4048 (20 May 2009)

mjw1476 said:
			
		

> thanks for clearing that up! ill just crack on now with trying to rid myself of this algal bloom! worked out its poor circulation of the co2 and inbalances from a few weeks ago. going to get some excel to try and kill some!
> 
> as its taken hold now will it ever go with a crew of 20+ cherry shrimp, 3 large amanos, 2 otos. and im trying to get hold of some true siamese algae eaters, dont want to get the wrong ones and them sit in the corner doing nothing!
> 
> ...


Here's my (rather controversial) position: Stop using fish and other critters to get rid of algae. Learn to grow plants well. Healthy plants rebuff algal blooms. Many of us have no algae eaters and yet we have no algae. There is a direct relationship between the health of plants and the level of algae in the tank. Hair algae  is cleaned with a bit of elbow grease and pruning, and is kept at bay by having high, stable levels of CO2. No eaters are necessary for this. Furthermore, high CO2 is not really compatible with many inverts so by throwing critters in the tank, you actually limit the amount of CO2 that can be injected into the tank, so in a way this becomes a self fulfilling prophecy... 8) 

Use a toothbrush and gently twirl the head around the filaments. No need to worry, many toothpaste brands are made with algae so feel free to continue brushing (the hair filaments might actually serve as bio-floss).  :idea:  

Cheers,


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## mi5haha (20 May 2009)

a1Matt said:
			
		

> My mistake, you never said you were in Germany. Sorry about that.  It is nice to see poeple from all around the world here on the forum
> 
> I am curious what in hard water could make it easier to grow red plants.
> I assume (and I am only making a semi-educated guess here) that it is something that could always be added separately.
> For instance, GH is made up of either calcium or Magnesium (or a combination of both).  When my GH drops I dose Magnesium and Calcium and my plants clearly do better with it.



Hard water contains a lot of calcium and magnesium so we don't need to add them additionally. However, some plants cannot live well in such water so choice has to be carefully made (after tried a dozen of plant varieties so finally you would know who could grow in hard water. HC is difficult for example). However, when dosing K in hard water, it is said that K may check Calcium absorption when either of it hit a high level. So still watching on that.


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## ceg4048 (20 May 2009)

mi5haha said:
			
		

> Hard water contains a lot of calcium and magnesium so we don't need to add them additionally. However, some plants cannot live well in such water so choice has to be carefully made (after tried a dozen of plant varieties so finally you would know who could grow in hard water. HC is difficult for example).


HC grows absolutely fine in hard water. The problem with HC is that it is a poor CO2 feeder whether in hard or soft water.

We have also determined that hard water may not have Magnesium. Unless you have a reliable test kit it is not certain what combination of Calcium + Magnesium is in the water. It could be very high in Ca and very low in Mg, or the water could have an even level of both or it could be high in Mg and low in Ca.

So it's entirely possible that you grow a plant in hard water and it could suffer either an Mg or a Ca deficiency. A combination of this plus poor CO2 distribution could cause HC (and other plants) to fail thereby giving the illusion that HC is hard water intolerant. 



			
				mi5haha said:
			
		

> when dosing K in hard water, it is said that K may check Calcium absorption when either of it hit a high level. So still watching on that.


This is also proven to be false. Potassium in no way prevents Calcium uptake when both are fed in unlimited quantities in submerged aquatic plants. The report of high K reducing Ca uptake comes from studies of the Apple tree,which is susceptible to low Ca content. This cannot necessarily be applied to aquatic plants. 

What is true in terrestrial plants is that high Ca content in the soil reduces uptake of many other cations (positively charged particles) such as sodium (Na+), potassium (K+), magnesium (Mg++), Ammonium (NH4+), iron (Fe++), and aluminum (Al+++) for uptake by the plant. High K+ applications have been known to reduce the Ca uptake in apples trees. Again, this cannot be automatically extrapolated to aquatic plants.

We must also remember that as long as there are no shortfalls of nutrients, plants are able to internally regulate the optimum ratios of the elements. It is not necessary for us to regulate the dosages. This is an often overlooked advantage of the EI dosing scheme. Additionally, plants have been shown to perform brilliantly over a wide range of internal K:Ca:Mg ratios. It is only when there is a deficiency that difficulty arises. Concentrate on avoiding deficiencies and one never has to worry about Ca toxicity.

Cheers,


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## mjw1476 (20 May 2009)

thanks for the alging ridding tip, ill crack on with that at the weekend, sure ive got a spare toothbrush somewhere, not overly keen on using it again!!

my drop checker often reads very light green or yellow with the fish being fine so may be the distribution which im going to get a koralia 2 to rectify!

ill try and get some photos to show you what im dealing with, hopefully that will give you a better insight!

cheers

Matt


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