# London hard water and Dosing



## dingweding (11 Jun 2009)

I set up a new plant tank a month ago.  90L,  pressurized CO2 with glass disffusor.  2 bubbles per second.

the light is 2x 24w 6500k and 1x24w 4000k.  Is on 4 hours , off 2 hours then on 4 hours again.

i try to dose EI in the first two weeks, as there is some shirmps in the tank, i worried big water change will stress them, thus i only did 20% water change per week, i cut down the dose to twice per week, with less amount as well.

the first a few days, plants goes fast, but never pearl.  Soon all the plant stop growing, some fragile one like HC melt and died.

i thought the problem is too much nuritient accumulated? but ppl said that should not be the problem.
the tank now has some fuzzy and hair algea, but not a lot.

i did a 60% water change last sunday, did not add any fert, but add some surface agitation.

just test my tank water, as London water is very hard.

tap water PH is 7.7 , GH 17, KH 11, NO3 50ppm
tank water PH 7.4, GH 12, KH 10, NO3 0ppm

i was told plant can not do well in such hard water, will this be the problem?

As there is already NO3 in the tap water, should i still dose KNO3?
Meanwhile, the water is so hard, should i still add Mg?

Many thanks


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## ceg4048 (12 Jun 2009)

dingweding said:
			
		

> ...Soon all the plant stop growing, some fragile one like HC melt and died.
> i thought the problem is too much nuritient accumulated? but ppl said that should not be the problem.
> the tank now has some fuzzy and hair algea, but not a lot.


Yes, the people are right. It has nothing to do with nutrients. The people also say that melting is due to poor CO2 and too much light. They're right about that as well. Lower your light and add more CO2.


			
				dingweding said:
			
		

> i did a 60% water change last sunday, did not add any fert, but add some surface agitation.


This is exactly the wrong thing to do.


			
				dingweding said:
			
		

> just test my tank water, as London water is very hard.


Hard water makes no difference. testing will only make more trouble for you.


			
				dingweding said:
			
		

> tap water PH is 7.7 , GH 17, KH 11, NO3 50ppm
> tank water PH 7.4, GH 12, KH 10, NO3 0ppm


A pH drop of only 0.3 units is a sure sign that your gas injection rate is abysmally poor. I don't believe any of the NO3 readings. They are completely useless. Resume dosing as stated in the tutorials, add more CO2, throw away the test kits and reduce the lights.


			
				dingweding said:
			
		

> i was told plant can not do well in such hard water, will this be the problem?


Here is a tank with GH 18, KH 10, NO3 60ppm and PO4 10ppm - this proves that everything you have been told or suspect is incorrect.







			
				dingweding said:
			
		

> As there is already NO3 in the tap water, should i still dose KNO3?


OK think about this question; since there is already food in your belly should you still eat?


			
				dingweding said:
			
		

> Meanwhile, the water is so hard, should i still add Mg?


You are worrying about the wrong things. Worry about the fact that you have too much light, not enough CO2 and possibly not enough flow/filtration.

Cheers,


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## aaronnorth (12 Jun 2009)

so far i got everything right then


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## dingweding (13 Jun 2009)

LOL, Aaron, we will wait and see  

I notice there might be a problem in my filter. i put a bag of activated carbon in my filter, i think it might get rid of all my fertiliser?

meanwhile, there is a bag of peat in my fiter, which was left nearly half year ago when i use it to decrease PH.

last night, i discard the carbon, and put a new bag of peat to replace the old one.

any suggestions?


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## ceg4048 (13 Jun 2009)

Yes, get rid of the peat and forget about it forever, because your CO2 will drop the pH more effectively than any mangy bag of peat could ever dream of doing. That bag of peat, as well as that bag of carbon also block flow through the filter. The importance of flow can hardly be overstated in a high tech tank, so get rid of both bags in order to improve your water throughput. :idea: 

Cheers,


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