# Water chemistry question -- KH



## An t-iasg (Jun 3, 2005)

I'm getting ready to start my planted tanks and I have a question about KH. My pH out of the tap is 8.2; after aging, it's 7.8. The GH from the tapwater is 10 dGH, and the alkalinity is 3 dKH. 

I mix my tapwater half-and-half with RO water from the grocery store. This is fine for my 5 gallon betta tanks. If I start a bigger tank I may want to find something that would like my tapwater bettter. (yes I know Rift Lake cichlids would work but I don't know if I'm ready for them!)

The parameters on my tap-and-RO water are 1 dKH, 4dGH, and 6.8 pH. I know that chemicals aren't good to alter pH and you end up "chasing the dragon", and that's why I began using RO water. The bettas are used to this now and I don't really want to change the way I mix the water. It has been fine so far, but now with all the plants I have planned, I'm wondering if the very low KH will cause the pH to fluctuate, specifically as I use Flourish Excel. I only used it twice a week when I had a few crypts. Now with all the new plants I may need to use it more often and I don't want to run into trouble with a pH fluctuation. 

I have experimented with adding baking soda to the water. (experimented with water in a gallon jug, not in the tank !!) I was surprised at how little baking soda was needed to really raise the KH. I could try this method for stabilizing my KH but I would like some help, if you think this will work for me.

I've also downloaded Chuck Gadd's calculator but don't really know how to use it yet. Any tips will be welcome!


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## Cavan Allen (Jul 22, 2004)

I don't understand why you'd want to anything other than maybe bump up the KH a bit. We are lucky to have very good planted tank water here. 

I use Seachem Alkaline buffer to raise my KH to 4. Three is probably the minimum KH I'm comfortable with, and 4 works well. 

Flourish Excel doesn't alter ph, so you won't have to worry about that.


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## Bert H (Mar 2, 2004)

I'm not sure I understand what you're trying to accomplish?? You're adding RO to lower your KH, then you're adding baking soda to raise it back???

There's nothing wrong with your parameters out of the tap, ie, GH10, KH3. While I have never kept bettas, I don't think a KH of 3 is bad for them. 

As far as your plants go, they will do quite well with KH3 water. And if you plan to add CO2, KH3 will also work great with it, while if you drop it below that, then you will have problems with pH swings. If all you plan to use is Excel, it's a moot point, and Excel doesn't affect pH, to my knowledge. 

Chucks calculator is good, but IMO, our fertilator here is easier to use. Have you looked at that? For plants, basically you want to have your nitrates (NO3) around 10ppm, and your phosphates (PO4) around 1-2ppm. Add a little potassium (K), and dose trace element mixes. How much (or how often) you add depends primarily on your lighting. Your lighting will also determine whether you ultimately need CO2 or not. High light tanks really need CO2 to keep things balanced.


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## An t-iasg (Jun 3, 2005)

Thanks, everyone! I'm using the RO-tap mix to lower the pH without chemicals. It's worked well so far but I was concerned about the KH of only 1 dh as I begin a planted tank. I used Excel twice a week before (I have stopped for now because there is only one crypt in the tank now and I didn't want to fuel a green algae bloom.) 

When I used Excel more than twice a week, my pH dropped to about 6.4 and I wondered if the heavy dosage of Excel caused it. From my understanding, Excel is an acid. Is that right? I know the Seachem website says it won't lower pH. Maybe it didn't in my case -- I was just wondering what did. I don't plan to use CO2 with these tanks.

So my options are -- use Excel only twice a week; raise KH of the RO-tap mix slightly, to 3 dh (is that worth it?) or maybe once a week, apart from the regular water change with RO-tap, change maybe a half gallon using aged tap water, to replenish the buffers? 

What are your thoughts? The fish are used to the RO-tap mix and I don't want to stress them. 

I did find the Fertilator page. I will still need to look at it a bit more to understand all you can do with it.


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## An t-iasg (Jun 3, 2005)

P.S. I'm not using baking soda now, just wondered if it's worth it to only try and raise my RO-tap mix a few dKH. I did look at the fertilator some more. It seems like I need to add almost three times the Nitrogen I have been adding.


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## An t-iasg (Jun 3, 2005)

Another update: I've decided not to use baking soda to raise KH either. The amount I would use is less than 1/8 teaspoon, which is too hard to measure accurately. Plus, from some reading, that may end up putting more sodium ions in the water than the fish are comfortable with -- they probably will be ok, but there's no way to tell for sure. So I won't try that method. 

My tank water is a half-and-half mix of tap and RO. I'll gradually decrease the RO amount and increase the tap amount so I have some more buffers in the water. Maybe my pH fell not because of the Excel, but because my buffer level wasn't good enough.


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## Phil Edwards (Jan 22, 2004)

An,

I would recommend slowly phasing out the RO water. A pH of 7.8 is just fine for bettas and you're better off not modifying your water for the long run. A KH of 3 is also just fine, no need to modify it either. Your plants and fish both will appreciate the long term stability and increased electrolytes in the water.

As far as the Excel causing a drop in pH, it's most likely due to the benefit it's having on your plants. By adding that little bit you're giving the plants enough to grow and then they're using chemicals out of the water that are causing it to acidify. Yes, Excel is an acid, but only in a broad sense and is a very weak one at that. It shouldn't have any affect on the pH of your water and hasn't for me when I've used it, even in copious amounts. 

Did I read correctly that your tanks are in a place where you can change the lighting? Home Depot and Lowe's both sell little "button halogens"; little 20w round spotlights with a low profile for use in lighting spaces under cabinets. They're very economical, attractive, and offer great lighting for small tanks. I would recommend them highly for your 5.5g tanks. The other thing I would suggest is trying to get your stemplants to grow emersed, that way they'll get more light and atmospheric CO2. If you haven't already, check out Diana Walstad's book "The Ecology of the Planted Aquarium". While it wasn't written specifically for them, the method is perfect for small Labyrinth fish like Bettas. 

Regards and good luck!
Phil


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## An t-iasg (Jun 3, 2005)

Thanks, Phil! As I do water changes, I will gradually use more tap than RO water. I'm setting up the second betta tank today. I poured the jugs on Friday. I made them half tap and half RO, because that's how the existing betta tank is set up. Then, as I do my water changes once a week for each tank (or possibly twice a week -- have to watch the parameters) I will gradually cut down on the RO water. I thought that I would go less crazy :lol: if I change both tanks over to more tap water together. Then I could make 2 jugs of water and not worry about which tank needs more tap than RO for a particular change. If necessary, I'll check out the product Cavan mentioned too. 

There were halogen lights above the tanks (the under-cabinet lights). The bulbs were 25 watt, on low brightness, using the rocker switch. I had a lot of algae with this light and then the ultimate bad "algae", cyano. That's when I removed the halogens and put the fluorescent strip in. I didn't think halogen lighting was in the right spectrum for plants. I have read about many causes of cyano (slow water movement is one, which I have for the bettas) but I haven't had any other outbreaks since.


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