pH Control

[aquahobbist]

Beginners Info Sheet
++++++++++++++++++

Tank Dimensions (LxWxH): 4 ft 55 Gallons
Lighting Intensity(No of Watts) : 250 W
Type of Lighting (FL/PL/MH) : MV
No. of Hours your light is on: 12
CO2 Injection Rate (bps) : 1.5
Type of CO2 (DIY/Liquid/Tank) : Tank
Method of Injection (e.g. Diffusor/Reactor): Diffuser
Substrate Used : Flourite mix
How Thick is your base fert : 1"
How thick is your gravel : 2"
Liquid Fertilizers Used : Seachem
Frequency of fertilization : twice a week
Tank Temperature : 25 C
Type of Filter (overhead/internal/canister) : Canister Magnum 350
Filter media used : Carbon
How long has your tank been set up : 6 months


Chemical Properties (Fill what you can)
---------------------------------------

Carbonate Hardness (kh): 3
Total Hardness (gH): 4
PH : 7.2-7.4
NH4 (ppm):
NO2 (ppm):
NO3 (ppm):
PO4 (ppm):
Fe (ppm): .4

Bioload (Your Fish and Plants)
------------------------------

21 Rasbora Espei
4 Gold Barbs
7 Cherry Barbs
2 Rams
2 Farlowella acus
6 amano shrimp

Fully planted maybe 24 spieces of plants.

-------------------------------------------------------------------

Beginners Info Sheet
++++++++++++++++++

Tank Dimensions (LxWxH): 20" 20 Gallon Tall
Lighting Intensity(No of Watts) : 40
Type of Lighting (FL/PL/MH) : FL
No. of Hours your light is on: 12
CO2 Injection Rate (bps) : .5-1
Type of CO2 (DIY/Liquid/Tank) : DIY
Method of Injection (e.g. Diffusor/Reactor): Airstone
Substrate Used : Flourite
How Thick is your base fert : 2"
How thick is your gravel : no extra
Liquid Fertilizers Used : none
Frequency of fertilization : none
Tank Temperature : 25 C
Type of Filter (overhead/internal/canister) : Hanging filter
Filter media used : Carbon and sponge
How long has your tank been set up : 1 week


Chemical Properties (Fill what you can)
---------------------------------------

Carbonate Hardness (kh): 3
Total Hardness (gH): 3
PH : 6.1
NH4 (ppm):
NO2 (ppm):
NO3 (ppm):
PO4 (ppm):
Fe (ppm):

Bioload (Your Fish and Plants)
------------------------------

no fish at the moment
Some riccia, Microsorium pterpus, and Vals.


----------------------------------------------

My Problem

I have been having a problem getting my pH to drop in 3 of my tanks to drop below 7.2. This is causing problems for me because my tap water has a pH of 6.8. I'm injecting CO2 into all three tanks and I still can't get it to come down. It holds nice and steady at 7.2 though. Also in my house I have a recently set up tank, the second one that has a DIY CO2 injections and the pH is down to 6.1. CO2 concentration is like 50 something ppm while in my other ones, 2 DIY 1 tank the CO2 concentration is only like 5 or 6 ppm. My dad also has 2 tanks in the house and his pH runs 6.5 or around there. I live in Oregon and our water from the tap is soft 3 kH and 6.8 pH.

Of the three planted tanks one uses a Dupla reactor, and the other 2 the Plant Grow diffusers that wind back and forth a whole bunch and 2-Liter coke bottles.

I can't seem to figure out what the problem is or how to lower my pH because Im already cranking out the CO2 and its just not happening so your help would be most appreciated. Thanks.

Kevin

[cheeboonyong]

I'm not sure why you can't bring your ph down but before that: why do you wish to bring your ph down? Supposedly your CO2 is at 50 ppm, so there's no point bringing down your ph via injecting more Co2. The CO2 is already more than sufficient.

In any case, I suggest you try adding peat. It will bring down your ph by releasing acids (I think). Do tie up the peat in stockings to prevent clouding.

[Sleepy_lancs]

Hi Kelvin,

Was wondering if you would like to try this first:

1. Take some water from your tank and pour it into a plastic cup and leave the cup aside for 24 hours.

2. after 24 hours, make sure your tank's CO2 injection is running for at least 2 hours, then take a PH measurement.

3. Take a PH measurement of the water you put in the plastic cup.

4. Compare the 2 results. If the difference is 1.6 to 1.7 then the CO2 in your tank is about 20 - 30 ppm.

Hope this helps

[aquahobbist]

Thanks for that tip about leaving the water out. I'll let you know how it goes.

I dont want to add more pH to that one I want to add to the other three that according to the pH kH relationship says there is only like 5-6 ppm CO2. And peat really only works best on harder water I believe?

If that suggestion does show a difference of 1.6 or so, is there any way of explaining why the pH is still high because Im not adding any buffers or anything?

[geoffrey]

Something is neutralising your water to, well about 7 pH. What is your gravel type? Any chance that you might have added stuffs with carbonates in it without knowing? Like coral chips, shells etc.

Carbon in your media? Activated carbon?

[eric_kclee]

Kevin,

Sigapore water is very much similar to yours. For my 10G tank, I am already pumping 1bps CO2 to achieve 6.4-6.6PH.

Just thinking aloud, what are you doing with your 55G tank? 1.5bps?? ( my tank's KH and GH is very much same as yours).

Should you try increasing your CO2? what other thinks?
OR did you distribute your CO2 effectively around the tank by water current?
...I am no expert...

[zmzfam]

Kevin,

perhaps you should also change from a diffusor to a reactor for your 4ft tank? When the water reaches back to your tank, the CO2 should have been well diffused and the current would circulate the CO2 throughout the whole tank.