Question on Alkalinity and KH

Ok let me start by saying the KH to PH relationship in my tank seem really messed up. I have had calculated readings of over 100ppm of co2 and the fish are fine and dandy and the plants are growing but not much pearling.

I have started to do some research and would like someone to confirm if I have wandered upon the reason. Kits measure total alkalinity but the only part of the alkalinity that effects ph co2 relationship is Bicarbonate. My total alkalinity per the water department is 116 and the bicarbonate is 46. 116 would equal 6.5 kh 46 would = 2.6kh. I guess in most cases the majority of the alkalinity is made up of bicarbonate, but in my water bicarbonate is less than half.

My KH test kit shows KH of 6.5 to 7. I started shooting for a ph around 6.7 based on the kit. At 6.7 it seemed like there was little co2 in the water. I think I should be using the 46ppm number as my kh which would put my target ph at 6.3 or so.

I am now at 6.3 for ph the fish are doing wonderful and that plants are pearling much better. For the record 6.3 = 39 ppm co2 if the kh is really 2.6 or 98 is the kh is really 6.5. Right now I tend to believe my co2 is much nearer the 39 number.

Thanks

Rick

 

Re: Question on Alkalinity and KH

Guess no one knows about alkalinity and KH. I think I will get me a chemistry book. I am also going to try and find out what the other bases are in my water besides the bicarbonate. I would really like to be able to measure the bicarbonate too.

I live in ABQ NM and the Rio Grand river runs North and South through town. The water department web page has a map utility that lets you select the different water zones in the city and view the water report. I find it interesting that all zones on the east side of the river have almost all the alkalinity made up from bicarbonate an all the zones on the west side of the river only have about half the alkalinity made up from bicarbonatites.


Thanks Rick

 

Re: Question on Alkalinity and KH

Thanks Tom I will do that. HAHAH the KH test kit was the only kit I was still using. Doing EI for a couple months conviced me I did not need the others. The KH kit is now pretty useless at least for my water. Oh well I guess I will save a few dollars on kits.

I have a ph controller and I will not use it now excpet as a monitor. I am just going on the bubble count and monitor the CO2. If the water company pulled a switch and I got full bicarb in the alk the controller would gas the fish for sure.

I would suggest that anyone else that suspects a simular problem check with their water utility for information on the alk and bicarb. I am pretty sure they have the information.

What research I have done agrees with Tom's assestment. The low bicarb component of alk is pretty rare and localized.

Thanks Rick

 

Re: Question on Alkalinity and KH

Ok today I was down to PH of 5.9 with a measured KH of 7.5 and still have happy fish and I still have a fuzz or hair algae growing and some BBA. The algae it is thriving and plants while growing are not really taking off.

I am injecting about 180 to 200 bubbles a minute into a internal reactor. That seems like it should be enough? The PH has droped from tap 7.9 to 5.9. Yet I still have all the symptoms of low CO2 and have not stressed the fish at all?

I am thinking about adding baking soda to my tank and putting in a Known level of KH and injecting CO2 to 30PPM based on that. Any other suggestions or cautions on doing that?


Rick

 

Re: Question on Alkalinity and KH

I am not adding MG. I guess I can try that.

Rick