GH and KH / How They Affect Fish

[Twoapennything]

I have the API test kits for both GH and KH, but I cannot find the directions that came in the packages. I'm thinking I'm going to have to buy another set in order to get the directions on how to read the results; I can't find them online, although I've looked.

According to the Water Hardness Report from Denver Water, Denver's water would seem to run on the soft side as far as making lather from soap goes. Soap lathers up very nicely here. However, I do notice scale on all kinds of things, including my aquarium, but it doesn't say if scale is indicative of hard or soft water, or whether it's a good or bad thing when it comes to fish. It also doesn't give a specific hardness number or value.

The Denver Water Quality Report shows that nitrItes typically run around 1.0 ppm and nitrAtes run around 10 ppm. Those are the exact readings I got on my API tests this morning; I did a 70% PWC about four days ago. Chloramine runs at 4 ppm. Apparently they don't test for ammonia. Copper runs around 1.3 ppm.

I'm just wondering if any of these numbers mean anything to anyone who might be able to explain them, and who might be able to explain how they affect my tank. As I mentioned in another post, I've lost six fish over the past ten days. So something is clearly off.

Anyone know how to read the API GH and KH test solutions?

Thanks in advance for any replies.

 

[Fishguy2727]

KH dictates pH. GH is not as critical depending on what you are doing, breeding sofwater fish then yes, otherwise not as significant. What is the pH in the tank? If it is already acidic it is easy for it to drop quickly or crash, this can obviously stress or shock fish. The higher the KH/pH the harder it is for the pH to crash.

In most cases, unless breeding fish from the extremes, stability is more important than precision. By that I mean if you had tetras that prefer soft water but your water is hard it is more important that it stays stable than that you mess with it to get it down. Unless you dilute everything with RO/DI water you will only create a worse situation with a roller coaster KH/pH.

It is easier to get pH/KH up and keep it there than vice-versa. By adding baking soda you can easily raise KH and therefore pH as well. This would be useful if you had hard water cichlids, goldfish, etc. I have also used a bag of crushed coral in the filter just like carbon to help keep KH/pH up and stable. You MUST monitor pH and KH if you are going to mess with them at all. This is critical. I have seen and even had amazing tanks crash because of not monitoring KH/pH close enough. Make sure it is truly necessary and then be careful.

What fish do you have?

 

[jsoong]

Nitrites at 1.0 ppm in your tap is a problem!! Nitrites are toxic at 0.25 -0.5, so you might be actually poisoning your fish when you do water changes!

In a totally cycled aquarium, the nitrites will be metabolized (by the biofilter) in a few hours, but it would be prudent to not do large water changes so you don't get nitrite spikes. I would think 10% would be max with that kind of levels. <That would give you nitrite of 0.1 after the pwc.>

In addition, I would use a good dechlorinator that can bind ammonia & nitrites. <I use Prime.> Because of the 4 ppm of chloramines, you might need to adjust the dose of the dechlor ... since the chloramines will use up all the dechlor & you won't have anything left over to bind the nitrites with.

A standard dose of Prime (5ml per 50 gal) will detoxify 4 ppm of chloramines (per Prime website fact sheet). I would suggest at least doubling the dose in your water so your nitrites will be bound. <Seachem states you may use up to 5x usual dose for nitrite binding.>

Depending on your fish, it may be prudent to have a low level of salt in the water as salt will prevent nitrite poisoning.

A more involved method to make sure you have good water for your fish is:
1. Use a R/O unit to remove the nitrites & nitrates. <But you will have to add back a FW buffering salt as R/O will remove everything ... and you need a buffer to ensure pH stability, and for the fish's electrolyte needs.>
2. Pre-treat your water before use. You can keep a barrel of water & circulate it with a filter. Your aim is to create a biofilter in the barrel to remove the nitrites before you put it in your tank. You will prob. have to age the (dechlorinated) water for a few days before you can use it .... You will have to test for nitrites in the barrel to make sure it is zero.

Compared to your nitrite problem in the tap, GH & KH is nothing. As long as those stay stable, most fish can adapt.

The general instruction for KH or GH tests is to take a sample of water (5 ml in the API test) and add the reagent a drop at a time until there is a sudden color change. (Shake the tube after each drop.) <Starts blue then change to yellow.> The number of drops needed for the color change is the degree KH. <1 degree KH or GH = 17.9 ppm> If your 1st drop change the water yellow, then the KH or GH is less than 1 degree.

You only worry about the KH or GH if you are doctoring the water, doing live plants with CO2, or if you have extremely low KH (less than 2 degree) AND unstable pH. Otherwise, don't fuss over it.

 

[jsoong]

Incidentally, I would like to warn you about NOT using your tap water to feed an infant. The EPA guideline for nitrites in drinking water is 1 ppm. But nitrates are also converted to nitrites in the gut .... Personally, I think the total nitrogen is too high in that water for anyone under 6 months ... Babies can get very sick (or die) with high nitrites ....

This is the EPA's take on things:
Basic Information about Nitrite (Measured as Nitrogen) in Drinking Water | Basic Information about Regulated Drinking Water Contaminants | US EPA

 

[Fishguy2727]

Have you tested the nitrite actually coming out of your tap?

 

[jsoong]

The Denver Water Quality Report shows that nitrItes typically run around 1.0 ppm and nitrAtes run around 10 ppm. Those are the exact readings I got on my API tests this morning;

She had.

 

[Fishguy2727]

That is what the water company says is coming out (which may be the worst in a whole year). That doesn't mean the tap water actually has that much. Municipal tap water can vary widely based on recent rainfall, time of year, etc. Even the amount of chlorine and chloramine can be many times the usual at certain times of year or after a lot of rainfall.