Low KH and pH crash - Page 4 - Fertilizing

Edward · 06-25-2006, 03:37 PM

Quote:

Originally Posted by banderbe

That's interesting, I bubble 180 bubbles / min into my little 29 gallon tank. No leaks either as I just use a limewood airstone and can pull the tubing and see the bubbles coming out of the tube into the water. Even when I was using a reactor I had to push that much CO2 in order to get the one point ph drop.

What was your KH?

hoppycalif · 06-25-2006, 04:08 PM

I have found that having a good surface current, where the duckweed and bits of leaves move around at a very noticeable rate, requires a lot more bbs of CO2 to maintain the CO2 at the level I wanted. But, CO2 isn't expensive, so it doesn't bother me - I too use around 3-4 bbs of CO2 in a 29 gallon tank.

fresh_newby · 06-26-2006, 02:31 PM

I am interested in this theory, and testing it as well. I am about 9 weeks into a new 90 gal tank. The kH out of my tap is generally around 1, so I was using Bicarb to adjust then kept my pH controller at around 6.5-6.7 for a 28 ish CO2. This time I did not add the bicarb, so my kH is very low. My pH is now at 5.8, and I have the controller set at about 6.5, so it has been a day and a half since my CO2 even turned on! The pH has linearly drifted since my water change the other night from 6.7 to 5.8. I assume this is what many people refer to as a 'pH crash'. The chemistry doesn't make sense that it would truly crash; however. I am waiting to see if it plateaus. My fauna, corys, otos, rainbows, shrimp, Nerites, SAE, neons and swordtails, are all busy doing their thing and do not look at all stressed. yes even my Amanos are active. I am about to do a 30% water change just to see what it does. I am having issued with Eco complete andPO4 so I am down to 2 x's a week changes 30-50%. Anyway, will keep you posted. By the way, this is my first post

AaronT · 06-26-2006, 02:36 PM

Quote:

Originally Posted by fresh_newby

I am interested in this thoery, and testing it as well. I am about 9 weeks into a new 90 gal tank. The kH out of my tap is generally around 1, so I was using Bicarb to adjust then kept my pH controller at around 6.5-6.7 for a 28 ish CO2. This time I did not add the bicarb, so my kH is very low. My pH is now at 5.8, and I have the controller set at about 6.5, so it has been a day and a half since my CO2 even turned on! The pH has linearly drifted since my water change the other night from 6.7 to 5.8. I assume this is what many people refer to as a 'pH crash'. The chemistry doesn't make sense that it would truly crash; however. I am waiting to see if it plateaus. My fauna, corys, otos, rainbows, shrimp, Nerites, SAE, neons and swordtails, are all busy doing their thing and do not look at all stressed. yes even my Amanos are active. I am about to do a 30% water change just to see what it does. I am having issued with Eco complete andPO4 so I am down to 2 x's a week changes 30-50%. Anyway, will keep you posted. By the way, this is my first post

You may want to disconnect the pH controller for the expirement as the CO2 will likely not ever turn on. Do you have a bubble counter? If so I would start with 1/2 to 1 bubble per second and see how the plants and fish do.

I'm glad to see you made it over to APC as well. Keep us updated on your progress.

Brilliant · 06-26-2006, 03:23 PM

I have been running like this since day one (which is like 4-6 months ago, so I am no expert). I had someone tell me my pH was going to crash and I got all worried and added baking soda....thats all over with...but now I feel much better not adding baking soda. I added some crushed coral for added calcium...mainly for my snails..from what I read it also keeps pH a little more stable.

My co2 worked out to be exactly whats stated in this post. I dont run an air stone.

Seeing this thread makes me feel much better. I joined up and hope to learn alot from this forum. I dont really have much to contribute except...thank you!

fresh_newby · 06-26-2006, 04:23 PM

Thanks AaronT

OK well nothing was adding up! I did the water change, and my pH was stil 5.8. I knew something was off. I pulled out the pH probe, and hmmmm it was a point off! I recalibrated and am now at 6.6 with the CO2 going in 5/sec. YAY so my kH is at about 1-2 and I am back on track. Let this be a lesson...lol If the chemistry isn't making rational sense, and if the numbers are not what you would expect, always suspect the measuring device, beit a pH probe or a test kit. Question everything!

fresh_newby · 06-26-2006, 04:25 PM

and Brilliant...you are doing fine. If the plants and the fauna are happy and healthy, that is your validation. I am questioning everything right now because I am leery of my Eco/PO4 issue, so the last thing I want to do is be light on CO2.

Laith · 06-27-2006, 12:26 AM

Quote:

Originally Posted by fresh_newby

... Let this be a lesson...lol If the chemistry isn't making rational sense, and if the numbers are not what you would expect, always suspect the measuring device, beit a pH probe or a test kit. Question everything!

Definitely. If you're going to use test kits, calibrate them (test them against a known solution).

Also be aware that electrical interference can affect a pH probe's reading. On one tank if I turn off the lights my pH meter changes readings. On another tank turning off the lights makes no difference... So it's good to double check.

banderbe · 06-27-2006, 05:24 AM

Quote:

Originally Posted by Edward

What was your KH?

My KH used to be 18.. now it's 3.

Either way I had to put the same 3 bubbles / second into the tank.

Edward · 06-30-2006, 06:10 AM

Quote:

Originally Posted by banderbe

That's interesting, I bubble 180 bubbles / min into my little 29 gallon tank. Even when I was using a reactor I had to push that much CO2 in order to get the one point ph drop.

Quote:

Originally Posted by banderbe

My KH used to be 18.. now it's 3.

Either way I had to put the same 3 bubbles / second into the tank.

This could be another prove that the widespread KH/pH/CO2 tables are not correct. In your case achieving the same one pH drop required the same amount of CO2 even though the KH was 3 and 18. According to the tables the CO2 level in the 18 KH aquarium should be 6x higher. It doesn’t make sense, does it?

Thank you
Edward