[Dave B]

I can't get my ph below 7 for some reason. I have to add baking soda and calcium carbonate (also Turbo Calcium) and A little Epsom salts to get water up to 6˚Kh and 6˚Gh from tap water of 1˚Kh and 1˚Gh. Naturally my PH jumps way up after water changes, but it takes a long time to go down and doesn't go below 7. I have a new pressurized co2 system flowing through Gomer's inline DYI reactor at 1 bubble per second, which seems like a lot to me. Shouldn't the PH be going down with that much co2? Some of my plants do produce O2 bubbles after a few hours of light and co2 and some are growing like crazy some are not. It's hard to tell exactly what is causing growth in some and not in others because I have just started to dose with KNO3 and KH2PO4 so things are definitely in transition.

I would like to get the PH down to 6.8 or so to get 30ppm co2. Any Ideas or are my levels OK? Should I add even more co2? Are my plants just using it all up?

29 gallon
110 watt compact AH
lots of plants
50% water change per week

 

[Sir_BlackhOle]

Turn up the co2 slowly and keep an eye on things. You should be fine at 30ppm of co2.

 

[aquoi]

bring down the kh to 4-5 and the pH will go down easier.

 

[Gomer]

well, I have an extremely similar setup to yours. 29g, 110AH, same reactor inline. My KH is normally around 3.5 this time of the year. My bubble rate is ~ 1bps as well. I run on a pH controller, so my CO2 isn't always on. It is really easy to get the CO2 levels I want.

A few things to check out.
1) how much surface aggitation do you have?
2) Do you trust your pH and KH test kits?

 

[hubbahubbahehe]

How are your plants doing? If your plants are pearling and growing like crazy, i don't see a need to drop it down to 6.8...i mean from 7 to 6.8 seems small. My ph is 8.0 and I only wish i could get it down to 7.

 

[Corigan]

bring down the kh to 4-5 and the pH will go down easier.

My thoughts exactly aquoi. Buffering up 5-6 degrees on KH with baking soda is bound to make a huge PH spike as it is. I buffer up my KH from around 1 degree out of the tap to around 4-4.5 degrees and have no problems getting my ph down to 6.8-7 with 2 crummy Nutrafin Co2 systems on a 55G.

Matt

 

[hubbahubbahehe]

Yea, I'm also wondering why you add baking soda to your tank? It's not like you have 0 kh

 

[Gomer]

Hubba. read the first post.

"tap water of 1˚Kh and 1˚Gh"

That is VERY VERY soft.

 

[hubbahubbahehe]

whoops that is my bad. I just saw the 6 and was thinking to myself, "he wants to raise it?"

Well, if it is one, then why don't you put less baking soda so that it won't increase as high?

 

[gpodio]

OK, time for a silly question..... why do you want to bring your PH lower?

I mean, at 7KH and 7PH you have 20ppm of CO2, that's a good level IMO. Your plants are even pearling, why do you want to fix something that is not broken?

If you are targetting lower PH levels because of certain fish, then lowering your KH will be better, but it's not going to make much of a difference to your plants IMO. Otherwise try to reduce surface agitation to reduce the amount of CO2 that is lost. Still, I'd be happy with your levels, plus at 7KH, PH changes due to variations in CO2 levels are slight, often too little for our cheap PH test kits to give us an accurate reading. At PH6.8 you are borderline with what is considered too much CO2.

Just my two cents worth
Giancarlo Podio

 

[Dave B]

Yea, I suppose I'm getting too worked up about what I think the right numbers should be. Besides trying to figure out fertilizer amounts my tank seems to be doing pretty well. There isn't much surface agitation and who knows how accurate the A.P. tests are. The PH spike is what makes me feel like things are unstable. I'm going to add less baking soda to prevent the spike and keep the KH down around 4˚, then I suppose the Ph will drop down also.
Thank you all for the advise.

 

[Pigheaddd]

hey Dave,

whats your tap water pH? its about 7.4 in my area. honestly, i never test my kH etc, but i do test my pH once a week. my 20g tank with 130w pc 10hr/day, co2 with 2 bubbles/sec/24hr. pH is about 6.6~6.8.

my 5.5g tank is weird tho. 48w pc 9hr/day, co2 with 1 bubbles/sec/24hr. pH is 6.0 or even lower. my test kit only can test from 6.0 to 7.8 something like that, but im pretty sure kH is low. water is very soft. hehehe i judge kH by Tonina sp. :lol: it can survive and has new stems come out.

my 2.5g tank just set it up as my connection tank yesterday for short term. :wink: 26w pc 8hr/day(haven't turn on lights yet), co2 with 1 bubble/2sec. pH was as 5.5g around 6.0 or lower.

i think pH does matter with how well co2 dissolves in the water. :roll:

Tim

 

[hubbahubbahehe]

yo pighead you got pics of your tanks? on paper they sound terrific

 

[Pigheaddd]

yo pighead you got pics of your tanks? on paper they sound terrific

dude... sure... i'll take some pix of 2.5g when i have time. 5.5g needs a month or so... :twisted: ... 20g pix will update soon. sigh! you guys probably in sweet home at this moment. i'm still in the school library now. three exams/ couple essays due next week.

Tim