Light and water hardness

Watcher

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Apr 16, 2005
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I read a write up of an aquarist that moved from a location with soft tap water to a location with hard tap water. This individual used the same set up, plants, fish, dosing, CO2 fertilization, lights, etcetera but could not get as good growth from the plants.

This person stated that they had to increase the lighting to make up in part the growth they had in softer water.

I have very hard water. 8.5 from carbonates mainly. Some bicarbonates.

Has anyone come across any information or studies by Tom about light levels and water hardness?
 

matthewburk

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Oct 12, 2005
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Re: Light and water hardness

I would not call 8.5 very hard, I think that is just about optimum. My water is 30deg and I could grow most plants fine, but 2 weeks ago I reduced it to 15 by cutting it with RO water and there has been definete improvement in my ludwigia repens where previously the leaves would curl a bit. All my information is anectodal of course, but you should be able to grow just about anything with 8.5 I think.
 

Watcher

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Apr 16, 2005
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Re: Light and water hardness

Would you think that a hardness of 8.5 before I add any Calcium or Magnesium hard? I have about .1 GH in my tap water. So practically none of this PH rising additive that I need to dose for the plants is in the tap water that I have.

Once I start adding good levels of those I think I may hit a PH of somewhere in the 9 area.

Which means that where a ph of 8 is ten times more alkaline than 7, and 9 is ten times more alkaline than 8, I'll have over 100 times more alkaline water than a neutral level of 7!

If I had aquarium water that was 8.5 after I added GH additives I would not be very concerned. But starting at 8.5 before I add any GH additives(where none exists beforehand) seems to me to be throwing more hardness on top of already a beginning level of potentially detrimental high hardness.

I would just like to know if there is any scientific results on hard water causing an inhibition in utilizing light with aquarium plants. Or maybe diffusing it from the plants, or in any way that may prevent the plants from receiving the full benefit of the wattage of lighting that is provided.
 

Watcher

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Apr 16, 2005
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Re: Light and water hardness

Any known results about water hardness(specifically Carbonate Hardness not the traditional hardness (GH)) affecting light levels needed by planted aquaria?
 

VaughnH

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Re: Light and water hardness

I don't understand why you are adding GH additive when you already have hard enough water. You don't seem to need it.
 

Tom Barr

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Re: Light and water hardness

I'm not aware of any relationship here other than the total carbon is higher with higher KH.
With more light, more of the KH is used as CO2 becomes limiting.

When folks move around, they are introduced to different tap waters.
But.......dealiong with the tap water changes is a skill I've done very well with, namekly due to the Bay area's variation in tap water and our club's meetings and comparions.

While some plants species, Tonia, Erio's etc do not do well in harder water, most of the plants do.

GH was a non issue for me at 24 degrees.
But the KH was only 11.
I could all but about 4-6 species well(they grew, just not as well as in softer water)

My present tap is 20GH, KH 17.
I cut it with about 75%RO.

I like certain plants, the tanks are small, the RO is large, so it's justifiable for myself in this case.

So your plant choice makes a difference also.
I'd just cut the tap with 75% RO personally with your tap.
Add a little MgSO4 and that's it.

FYI.

Regards,
Tom Barr
 

Watcher

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Apr 16, 2005
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Re: Light and water hardness

I don't understand why you are adding GH additive when you already have hard enough water. You don't seem to need it.

I'm adding GH because I do not have the "traditional" term for hard water. I have less that 1 dGH in my tap water.

My "hard" water is caused by carbonate hardness. KH. I have a heck of a lot of carbonates and some bicarbonates in my water. But plants need GH, of which my tap has very, very little. So I add GH additives.

Tom, if I have to mix in RO water, that is just pushing the difficulty of maintenance over the edge. That is the proverbial straw that breaks the camels back. I'm setting up a 75 gallon heavily planted tank. So I will just go with my tap water and see what happens.

Can you name any plants that you think will not do well in high KH so I can avoid them?

Thanks for the advice.
 

Tom Barr

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Re: Light and water hardness

Well some species, the Erios, Tonias etc and some rotalas will not fair well.

Your tap must be softened prior for Ca removal, but generally this removed the KH as well.

Strange tap, re test to make certain it really is 1 degree Gh and very high KH, call the tap company also. This is a very rare case IME.

If you want, add about 1-2 degrees GH then.
The Gh builder Greg has or SeaChem Eq will be fine for this.

I do not think you need RO, but it's an option you have ruled out.

Still, there are most of the 300 or so species that will grow very well in hard tap water.


Regards,
Tom Barr
 

brad

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Aug 2, 2005
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Re: Light and water hardness

what about whole house softeners or the glass softeners we now see Amano using in his tanks that exchange for sodium ions? Are those really not a good option?
 

Watcher

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Apr 16, 2005
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Re: Light and water hardness

Ok, I retested and checked the local water report again. (Did it early last year too)

Bicarbonates 366 ppm
Carbonate 11 ppm
Calcium 2.96 ppm
Magnesium 0.65 ppm

This is how I test it at home as well (well not that precise, but the home testing definetly agrees with the basic level from the water report). The GH test turns green on the first drop, with KH I skip to 15 drops and go from there on testing to save a lot of time.

Our water comes from "deep wells located in the Simsboro Sand formation of the Carrizo-wilcox Aquifer."

We are only 90 minutes from Austin and that is Limestone City! Hundreds of tons of it stacked on the sides of road construction and blast sites. Also really close to tons of "Texas Holey Stone". I have some sweet pieces of the stuff. Interested in any Tom? :D
 

Watcher

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Apr 16, 2005
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Re: Light and water hardness

The website also says this about the drinking water treatment:

Fortunately, the source water for College Station is clean enough that the only chemicals used in water treatment are chlorine, added for disinfection, and fluoride, added for dental health. After the water is disinfected, it is pumped into the water distribution system, which includes two elevated storage tanks.

It does not mention any softening of the water. But hey, I don't know for truth.
 

Tom Barr

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Jan 23, 2005
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Re: Light and water hardness

Well, if you find some really nice pieces, sure.
The aquifer is strange though, lots of Carbonates and no Ca/Mg.

So..........where do the CO3's come from then?
Sodium?

There has to be a cation to go along with it.
I sort of doubt it's sodium also.

Regards,
Tom Barr
 

VaughnH

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Re: Light and water hardness

I googled carbonates, and learned that many metals make carbonates. But, that would indicate that there should be a very high level of some metal other than Calcium or Magnesium, and that should show up in the water quality report. The geologists among us should be able to tell us what metal ion that most likely is. Uranium???? Does the water glow in the dark?