# effect of no water changes on GH/KH



## Hoppy (Dec 24, 2005)

I don't believe you can raise the GH that much in only one month, just from water top offs. Much more likely is that something in the tank is releasing calcium into the water, like rocks or the substrate. What is in the tank?

In my experience, I had some "Texas Holey Rock" or similar rock in a 10 gallon tank, and the GH rose rapidly, so I know it can happen that way. Using gravel that is limestone would be even worse. Using gravel with bits of shells mixed in it would also raise the GH. The lower the water pH, the faster the GH would go up.


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## Erica (Dec 16, 2010)

All that is in the tank besides plants and driftwood is pool filter sand and a few rocks that I got from Rod at the driftwood store that he said wouldn't affect water parameters. My water evaporates extremely fast...I replace nearly two gallons every couple of days.


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## Hoppy (Dec 24, 2005)

How big is the tank? Two gallons is a lot of water from a 5 gallon tank, but not a 55 gallon tank.


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## Erica (Dec 16, 2010)

it's a 40 breeder. i guess i don't know what's normal for evaporation since my previous fish only tank had a glass hood, but to me it seems like a lot.


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## Hoppy (Dec 24, 2005)

Your evaporation is pretty high. That would be about 3/4 inch of water every other day. I typically got about 1/2 inch of water loss every 4-5 days on a 45 gallon tank, but a taller tank. It may be that because your tank has a relatively large surface area to volume ratio you get more evaporation because of that. 

If you are losing about a gallon per day in evaporation, that's about 3/4 of the tank volume in a month, so you could be nearly doubling the amount of calcium and magnesium in the water per month with the topping off water. That is consistent with the GH increase you saw. The least expensive way to correct this would be a monthly 50% water change, with tap water. That would limit the maximum GH to about double the tap water GH.


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## Erica (Dec 16, 2010)

Yeah, I ordered an aqueon water changer so that I can start doing water changes on it.

I run a ceiling fan at night in the room. Would that affect evaporation?

Also, I have some ludwigia coming...probably about 20 stems. Will adding stems help lower the GH in any significant way?


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## Hoppy (Dec 24, 2005)

Moving air will evaporate water faster than still air - you blow dry hair, for example. No plants I can think of are likely to have a measurable effect on the GH. Just establish a habit of doing a 50% change once a month.


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## AirstoND (Jun 17, 2011)

Erica said:


> Yeah, I ordered an aqueon water changer so that I can start doing water changes on it.
> 
> I run a ceiling fan at night in the room. Would that affect evaporation?
> 
> Also, I have some ludwigia coming...probably about 20 stems. Will adding stems help lower the GH in any significant way?


 
Actually, might want to lower dGH before adding the ludwigia, or just try raising dKH (with baking soda) to equal parts with dGH. Otherwise might get calcification on leaves which also leads into algea growth.


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## Hoppy (Dec 24, 2005)

AirstoND said:


> Actually, might want to lower dGH before adding the ludwigia, or just try raising dKH (with baking soda) to equal parts with dGH. Otherwise might get calcification on leaves which also leads into algea growth.


Do you have any reference that discusses this? I don't think it is correct, but I could be wrong.


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## Erica (Dec 16, 2010)

I'll start doing water changes. Thanks Hoppy 

I don't have any calcification or algae on the plants I have now and I can't see why ludwigia would be any different.


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## AirstoND (Jun 17, 2011)

I understood the original post as wanting to lower dGH, and I suggested raising dKH so calcium/magnesium in solution is taken up by plants via carbon dioxide photosynthesis of ADDED dissolved carbonates. 

I understood plants soaked up necessary calcium for cell wall growth, important for ludwigia's long stem cells, hence why ludwigia is preferably grown in acidic soft water conditions because it takes up calcium easier:biggrin:. The relatively smaller stemmed java moss prefers neither high or low pH because it doesn't need similar growth conditions.

I'm sure the reference is somewhere on these links: 
http://www.americanaquariumproducts.com/Redox_Potential.html
http://www.tropicalfishkeeping.com/aquarium-plants/biogenic-decalcification-66627/

excerpt.....

The OH- combines with calcium bicarbonate [Ca(HCO3)2] in the water causing the precipitation of calcium carbonate (CaCO3) on the top of the leaf. In hard, alkaline water, this reaction, which is called "biogenic decalcification," may be so great that crusts of precipitated CaCO3 may weigh more than the underlying plant. I have seen CaCO3 deposited as small white "pimples" on the leaves of Egeria densa and Ludwigia repens when they were grown in hardwater under intense light.

Some aquatic plants (e.g., Myriophyllum spicaytum and Vallisneria spiralis) that use bicarbonates do not polarize their leaves during bicarbonate uptake.

There we are.

Byron. 

The internet makes everyone a Theoretical Physics Professor in the endless search for knowledge...I feel like the Cate Blanchett character at the end of Indiana Jones 4.

Peace and Love


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## Erica (Dec 16, 2010)

That's all a bit over my head, lol. I planted the ludwigia today and did a big water change to start getting the GH down. I guess from there I'll just see how things go.


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