# Does hard water slow plant growth?



## Chrispowell (22 Apr 2017)

Hi all, 

My tank which I consider is high tech dosnt seem to have a great growth speed, rotala takes about a week to show new growth after a trim and although most of my plants are slow growers my other stem that I'm not sure on its name also seems to take 6-8 weeks to hit the waters surface (about 18").

Tank specs

Co2 approx 2bps
Light t5 39w
2 T5 tubes for 8 hours
6 T5 tubes for 2.5 hour burst
EI ferts 

My water is quite hard though, approx 18GH

Will switching to RO water make any difference??

Thanks


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## Tim Harrison (22 Apr 2017)

Some folk are adamant they get better growth in softer water. But there are probably a large number of confounding factors that influence growth so it's difficult to pin slow growth down to one particular factor like hard water.
For instance, some find that successfully growing certain plants in very hard water requires more CO2.
I've lived in very hard water areas most my of life and found that I can pretty much grow anything, even those species traditionally thought of as being exclusively soft water plants; my stems usually grow like the weeds they are.

However that said, all our aquariums are different with different parameters, and you my find that what will grow well in one scape may not do so well in another.
When this happens I tend to be philosophical and just try different species until it works.

So short answer is, no it shouldn't make any difference.


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## zozo (22 Apr 2017)

There are certain sp. of crypts originating from very calcareous streams in SE-Asia and grow significantly beter in hard water.. 
I need to look it up, can't readily think of the specific name, but one of them is one of the biggest crypts around i believe..


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## Tim Harrison (22 Apr 2017)

That's very true. They are capable of synthesising carbon from bicarbonates. Many other species have been found to do the same, such as some species of anubias, vallis, elodea, ferns and mosses. So they all usually thrive in hard water.


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## zozo (22 Apr 2017)

Some Potamogeton sp. also, i know it from the P. perfoliatus, these develop a crust of calcium on their leaves at higher pH above 8
For many pond owners an indicator for monitoring pH value.. I hapen to have it, my pH is averagely above 8 and this seems to be more hindering the plants than hard water. Hard water is ok and you'll never have a calcium deficiency.. 

If i'm correct the pogostemon helfiri also does beter in harder waters. I can't grow it and my gH is < 8 DgH it always dies on me.. Can't think of another reason why.


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## Tim Harrison (22 Apr 2017)

I remember we had a pretty good discussion about it a while ago
https://www.ukaps.org/forum/threads/white-fungus-like-dots-on-anubias-making-my-fish-sick.37756/


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## zozo (22 Apr 2017)

Tim Harrison said:


> I remember we had a pretty good discussion about it a while ago
> https://www.ukaps.org/forum/threads/white-fungus-like-dots-on-anubias-making-my-fish-sick.37756/


Yup remember that one too..  How do you keep track of all those topics.. Bookmark them?. Lately discovered with the anubias it might not be the anubias itself doing that, but likely the algae on it. Because this accumulating calcium seems to be a thing of plants with high metabolism only. Thus fast(er) growing easier plants.  At least that was the case in my tank, the higher pH indication and than first green spot algae on the anubias leaves followed by a yellowish crust of calcium deposite. Also had this same crust on several antricite colored rocks growing aufwuchs or algae. The rock color made it realy obvious.. 

All tho it improved, because algae growth is less now since the tank matured properly. Only got slow growers in this tank, algae is the only one comming fast..


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## Tim Harrison (22 Apr 2017)

Eidetic memory...


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## zozo (22 Apr 2017)

I remember most of them too, just not how to find them back in a minute. Great job Tim..


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## HiNtZ (30 Apr 2017)

I've found that growing in softer water is easier, I don't put it down to the softness - more I feel it's down to the fact that since I filter my water I'm starting with a blanker canvass in regard to what's in the water to begin with (phosphates, nitrates, silicates) so I can get my dosing more on point.


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