I am having a really hard time lowering the KH in my ten gallon tank. It is over 300 and nothing is working. my pH is very high and unstable because of it(around 8.2 ish). At my house we have extremely soft water (5-10) and extremely hard water (over 300). I am going to start mixing the two hard and soft waters together for my tank. Some one recommended to take a look at this site called Roark's Experimental Puddle, which is a koi pond site which the people running it definatley know what they are doing. This is what they reccomend for lowering KH:

KH Reduction Method #3: Use Of Acid
The addition of nearly any strong acid to your pond will result in the rapid consumption of carbonates, thereby reducing the KH. Acids preferentially attack the KH value while leaving the GH value intact. While virtually any acid will work, hydrochloric acid is the most suitable and the safest from a chemical standpoint for fish and plants. If you are considering this method, please read and understand the section on Acid Safety first.

Hydrochloric Acid
Also known as "pool acid", "muriatic acid" or by its technical name, "hydrogen chloride", hydrochloric acid (symbol HCl) is a simple two-element acid consisting of a single hydrogen atom bonded to a single chlorine atom. This is an exceptionally strong, stable acid whose byproducts are largely non-toxic to fish and plants. Five strengths are commonly available, as follows:

8.7% solution . Called "spa-strength pool acid", this is a rather dilute HCl designed for use in spas, hot tubs and other small bodies of water. This strength is ideal for making controlled adjustments in ponds in the sub-2500 gallon category. It can be obtained from your local pool supply or hardware store in 16 and 32 ounce containers. It is quite cheap. Locally I obtain this for about $5 for a 16 oz bottle.... which easily lasts a year or more.

I am always really nervous abouting adding chemicals, especially strong ones to my tank. They have a fornula on the site which if I try hard enough I can probly find a dosage for ten gallons. This koi site is talking about treating ponds tho..I'm afraid I currently don't have any goldfish in my tank but I do have two little tetras named Ruby and Rummert. I think if I do this I should keep them some place else? What do you guys think on this idea? I need more experts opinions.

No opinions? I think that this is a first..

Good luck with your KH.

I've not even read about what you're going to attempt, so I can't really give any advice/comments, except wish you luck.

I am interested in the results, so do post back, whether it's successful or not.

Slugger

Thanks slugger I am too scared to actually go thru with this, but may use it as a last resort. I am going to start the procesess of elimination with variables. AKA: I'm going to start doing frequent water changes and add a little hard water to the tank since mine is too soft.

Hey I just noticed that you are from Hong Kong. That's pretty neat

It couldn't hurt to try it outside the tank. Woudn't try it in the tank tho.

Hi Kissy,

Those water changes are great,

Yup, I'm from Hong Kong, which is OK. I suppose every place has good and bad points... Right now the weather is too hot and humid, so I got the air-conditioning on all the time.

How are things in Arizona? I think I passed through it a few years back, not sure though. I was going from LA, through the desert, stopped at the Hoover ###### and ended up in Vegas!! I also went to the Grand Canyon separately, is this in Arizona? My memory is terrible!!! Thinking about it, I think it was in '97, but not sure...

Slugger

Hey data guru, thats a great idea! I have a 3 gallon bucket and a rubbermaid that is something like 15-25 gallons. I'm not too sure how big..I am just estimating but will find out before the experiment. Which do you think would be best to try for my ten gallon tank? Maybe both?

Also, how should I prepare the test tank? I'm guessing that I want the conditions to be the same as my fish tank...How do I do that? I don't have an extra filter or any type of aeration. I do have extra gravel tho.

Oh and Slugger: Arizona is very hot right now. It hit somewhere around 102 yesterday and will keep getting hotter. I've got a tan going on from the 30 minute walk home from school everyday...face, arms, and toes. I have a flip flop tan O_O Finally got the A/C going..before it just unbearable because my dad is so stingy. Yes, the Grand Canyon in in AZ I'm been there a couple times, but its boring to me just to look. One day I want to hike to the bottom...That's much more exciting! I just have to find someone crazy enough to acompany me

The first step would be adjusting your partial change water to GH around 100 by mixing your softened and unsoftened water. Three gallons should be fine, just measure to make sure where three gallons is in the bucket. Then let's look at your KH in the bucket and use Rourke's formula to see how much acid you'd need to bring it down to around KH of 120ppm. you'll probably need something to measure in milliliters or CCs. We'll also need to read his info carefully to see if there are any precautions when handing the pool acid and you'll need to make sure your parents are ok with it.

okay, I'll do that experiment as soon as I get the hardness up a little. I haven't tested the water yet, but last water change i added one gal of very hard water and 2 gal soft. I don't want to shock my tetras, especially since they don't like hard water much.

Hydrochloric acid, even when diluted to 0.1M, is very corrossive. Be careful with it!

yah I know I'm scared lol. I think I may hold off on this. The high pH will be okay for my goldie, but I'm not sure about my tetras. I am starting a tropical tank soon with a pH of 6.5 hopefully. If I can keep this steady I'm just going to leave it. But if I do go thru with this, my dad gave me the okay to experiment as long as I'm careful and wear protective stuff.