Confused about KH

[Killian]

How important is this? My tank right now has a very low KH - according to the chart with the API test it is 0-50ppm. I'm not sure what this means as a lot of the fish profiles say things like KH 5-20. Also my GH is higher (100-200ppm). What does this mean and shouldn't the KH and the GH be at least close?

 

[Killian]

Also even after adding Prime and doing a PWC, my ammonia still shows 0.50ppm. Will tests still show positive even after Prime de-toxes it? I assume the filter will take care of it as it cycles?

 

[jlk]

Lets start with the Prime. Prime simply converts ammonia (NH3) to less toxic ammonium (NH4). The API ammonia test doesnt distinguish between ammonia & ammonium so it will show a positive result if either/both are present. Just keep in mind, Prime only works up to @2ppm and this is only temporary (24-48hrs). If its been 2 days (or longer) since a water change, then you can assume the ammonia test is showing only the toxic form of ammonia and its time for a water change.

In respect to the KH & GH, your Gh is fine. Your KH needs a more specific reading. A Kh of 50 is perfectly fine but a KH of 0 indicates you have no carbonates (or buffers) and your ph is likely to be very unstable. I would suggest watching your ph levels to see if they remain stable or are swinging. Some ph variation is expected during the cycling process but it shouldnt be dropping drastically. If it is, then you may need to add a buffer to increase your carbonate (kh) levels and maintain a more stable ph.

I wouldnt be too concerned with KH values that are 'suggested' for fish unless you plan on keeping a sensitive/difficult species. Same goes for PH. Most fish are very adaptable and can handle a wide range of numbers as long as they are reasonably stable. Hope this helps! Heres some specific information:

Water Chemistry: pH, GH and KH What are they all? - Scott Thomson
Aquarium Chemistry; Calcium, KH, GH, pH, Electrolytes, Magnesium, Mineral Ions, Cations

 

[Killian]

Thanks for all the info! . My pH seems to be remaining fairly stable at this point. pH tests show 7.6 while high range pH shows 7.4. I'll keep and eye on the pH and as long as it remains stable I won't worry about GH and KH.

 

[RussellC]

If its been 2 days (or longer) since a water change, then you can assume the ammonia test is showing only the toxic form of ammonia and its time for a water change.

This may sound like picking nits (and probably is), but just as a point of clarification:

In the above instance, the test will show the levels of ammonia and ammonium combined -- not all of which will be toxic. How much is toxic depends primarily on the pH of the water, and secondarily (and a distant second) on temperature.

This is why you will here may fishkeepers say that ammonia is more toxic at higher pH levels. This isn't strictly true. Ammonia is equally toxic at any pH. What a high pH does is convert (safe) ammonium into (dangerous) ammonia.

Again, not trying to be picky here, just offering a small bit of clarification. I agree completely with everything else that was written.

Best!

 

[jlk]

Perhaps, you should read the rest of my post. The point I am trying to stress with using Prime is that its effectiveness only lasts a 24-48hrs- after this time frame, it is no longer effective at neutralizing ammonia and you can 'assume' (as I stated) that the ammonia showing up on a test is no longer in its less toxic form and that a water change is necessary. Furthermore, while ammonium may not be as toxic as ammonia, it still is NOT healthy for fish. PH is irrelevant. The only healthy is zero.

 

[RussellC]

Perhaps, you should read the rest of my post. The point I am trying to stress with using Prime is that its effectiveness only lasts a 24-48hrs- after this time frame, it is no longer effective at neutralizing ammonia and you can 'assume' (as I stated) that the ammonia showing up on a test is no longer in its less toxic form and that a water change is necessary. Furthermore, while ammonium may not be as toxic as ammonia, it still is NOT healthy for fish. PH is irrelevant. The only healthy is zero.

I did read the whole of your post, and as I stated, agree with it in its entirety.

All I was doing was pointing out that in absence of Prime, the assumption that whatever is showing up on an API test is ammonia is technically untrue. Some of it certainly will be, no question, but some of it will not be -- how much of each is present depending primarily on pH.

That's all I was trying to point out, and I think we really are in agreement here.

Best!