I need some help. Again. ph....

[FishyMatty]

In my 45g heavily planted tank I am having ph, kh and oxygen problems. First I have the co2 chart so I know what my co2 levels are. But the ph in my tank is swinging and I don't know how to stop it. Last night after a water change the ph was 6.8. My tap water is usually 7.2. This morning the ph was 6.0 or less. How do I get my tank to stay stable. I was using baking soda to buffer my water but I thought it might be bad because I kept getting fish gasping at the surface even with aeration(different tank). I know this is kind of vague but help if you can.

 

[Rex Grigg]

Stop. Put both hands on top of your head. Leave them there till you fully understand what I'm about to type.

You need to know the resting pH of your tap water. That means you need to put some tap water in a container and either aerate it for 24 hours and then test or let it set for 48 hours then test. Only then can you get an accurate reading of your tap water pH.

Second CO2 lowers pH. Are you injecting CO2? If not then no matter what the chart says you only have about 3 ppm of CO2.

Now, remove your hands from your head and tell us more about this tank.

What is the pH?
Are you injecting CO2?

Second. Go to www.theplantedtankFAQ.com and read the CO2 section.

 

[FishyMatty]

the co2 chart kh/ph doesn't mean anything if your not injecting co2? Then why do my fish look like they have no air when the co2 chart says there is 30ppm co2? I stopped co2 2 days ago because of this problem. The kh is so low it is not reading out of the tap. of in the tank for that matter.

 

[Squawkbert]

If you are not injecting CO2 (via DIY or pressurized), the charts are meaningless, you have ~3ppm CO2. If you have been adding Flourish (or is it Excel?), you have been adding carbon that can be used by the plants, but your dissolved CO2 is still ~3ppm or less (less is w/o any surface agitation).

Gasping fish may be related to O2 deficiency (again, due to lack of surface agitation).

So, in addition to what Rex has already asked for, please tell us what/how often you've been adding to the tank, what kind of lights (and how long they're on ea. day) and confirm that you have not been adding CO2 (assuming you have not).

 

[FishyMatty]

I have pressurized co2 for less than a week. Shortly after starting it I found a co2 chart and based on my ph/kh at the time and the fact that a couple of hours after lights on (5.7watt/gal) the fish were gasping for air sometimes at the surface sometimes just labored breathing. So I discontinued co2 thinking that the ph/kh relationship was enough co2 for the plant load. I also do dose excel daily at 1 cap full. on my 45 and 1/2 cap on my 20g.

 

[Squawkbert]

Filtration?

At least w/ the Excel dosing, your plants won't miss the injected CO2 (much).

I'm guessing that your KH test may not have been very accurate - this throws the CO2 calculation right out the window (often resulting in people adding lots more CO2 than they should).

Get a drop checker & 4 and/or 5dKH reference solutions for it (or just get the Red Sea one). These aren't instant, but they're pretty accurate as they use a pure carbonate/RO-DI water reference solution and indicator which lets you watch the pH change due to addition of CO2. As the CO2 conc. increases, the pH in the drop checker drops and the indicator changes color, letting you know this. When the indicator goes green in a 4dKH solution, you've got about 30ppm CO2. Blue means you aren't there yet, yellow means you're at or above ~50ppm.

If you search here and/or at APC for "Drop checker", you'll find lots of theory, DIY directions, sources etc.

 

[FishyMatty]

the test is a nutrafin test kit. it goes as low as 10ppm. Is it possible that a heavy fish load can produce enough co2 for a heavy plant load? Does the amount of dissolved co2 have anything to do with the oxygen level. By this I mean, During the day I don't have any surface agitation or aeration so the only o2 is whats produced by the plants. If I were to aerate the water and inject co2 that would cancel each other out right?

 

[FishyMatty]

anybody????

 

[Rex Grigg]

the test is a nutrafin test kit. it goes as low as 10ppm. Is it possible that a heavy fish load can produce enough co2 for a heavy plant load? Does the amount of dissolved co2 have anything to do with the oxygen level. By this I mean, During the day I don't have any surface agitation or aeration so the only o2 is whats produced by the plants. If I were to aerate the water and inject co2 that would cancel each other out right?

If the fish have room to swim then there are not enough fish in the tank to create adaquate CO2 levels.

The amount of dissolved CO2 has nothing to do with the dissolved O2 levels. This is about the 10th time and I'm about the 10th person to tell you that.

If you inject CO2 and aerate
the water it pretty much cancels out.

Now why the chart doesn't mean squat to you.

The pH/kH/CO2 chart is based on the assumption that the ONLY buffers in the system are bicarbonate based and that the ONLY thing lowering pH is CO2. If you have driftwood or peat in the aquarium it will add acids that lower the pH. Also some substrates will lower the pH. Some people add pH lowering chemicals thinking that adding them will add CO2.

IF YOU ARE NOT ADDING CO2 THEN YOUR CO2 LEVELS ARE AROUND 3 PPM. NO MATTER WHAT THE CHART SAYS.

I'm hoping that the color and larger font will make it easier for you to understand what you have been told three times.

 

[fresh_newby]

I love Rex's candor. :dance2:

Your Kh test is wrong likely...you need to test your pH by leaving the water out in a container as Rex described, and there is no what you have the fishload to sustain any type of CO2 concentration worth speaking of, so get those readings....maybe try a KH from Aquarium Pharmaceutics or another brand, and go from there. I wouldn't be afraid of acidity for the fish...my fish are in 5.7 and do fine...if anything, you are lacking O2. Make sure while you are sorting things out and if you don't have CO2 running, decrease your photoperiod so your lack of Carbon and higher light intensity doesn't send you into an algae bloom.