Water chemistry: High pH, low GH/KH?

[billg71]

Hi, all!

Have been absent a few months due to work and a remodeling project at home but I've finally gotten back to my tank. I have it sitting on the stand, hood finished. lights on and substrate placed, waiting for a plant package to get started. It's a 45 cube, actual capacity around 40 gallons less whatever space 4 bags of EcoComplete takes up.

Tested my tap water right out of the tap and found that the pH is 7.9 so tested GH/KH expecting them to be high but no, GH/KH both test at the lowest end of the range on the API kit, around 2 degrees or 35.8 ppm. Let a sample sit overnight and tested again, pH 8.0-8.1, no change in GH/KH. API pH test kit and Hannah Instruments pH tester (calibrated with their solutions) agree on the reading.

Since I'm doing a planted tank with Tetras and Angels, I'd like to get pH down around 6.8-7.0 while keeping GH/KH between 50-150ppm for the plants. Is this a reasonable goal?

Per Carl's articles, I'm planning to start with around 25% RO water, some Replenish, a mix of acid and alkaline buffers and add peat to the filter if necessary. I'm not going to have a lot of driftwood in the tank(3 small pieces) so don't expect much help there. No CO2 either, at least not for the time being.

So, is this a reasonable course of action? Has anyone had any experience with alkaline soft water and any tips to share? How often should I need to add buffer solutions, every water change or just test and add as needed? Suggested starting points for the buffers? Anything else I didn't think of to ask you'd like to share?

Thanks,
Bill

[Carl]

Bill;
Your "numbers" albeit uncommon, these are not unheard of either.
Likely with the introduction of a small amount of acids your pH will come down.

I agree with your use of 25% RO water. I would then add Acid Buffer to bring pH to your desired numbers. Then use a more natural means (Driftwood, Peat, Frog Moss, etc.) for maintenance of acid buffers.
Alkaline Buffer can be added to maintain a minimal KH buffer of about 50 ppm to prevent pH crashes.

I would suggest keeping pre-adjusted water on hand for future water changes too

Carl

[billg71]

Thanks, Carl!

Your articles are great, a big help. I've had to read some of them a couple of times to "get it" but I think I'm on my way. Redox is still confusing but I got that if I maintain good water quality and use UV sterilization I'm mostly there, looking forward to getting the TMC Vecton-2 from you next week. Looks like plumbing is getting complicated...

More questions undoubtedly coming.

Best and thanks again,
Bill

[munter1642]

Hi, I am Matthew from Australia

Like bill I have a 165 litre tank established for 4 weeks now. The only way I can get my kh to a good level of around 150ppm is to maintain the ph around 8.2

Is this ph acceptable with goldfish? Or is there a way of getting the ph down without sacrificing the kh?

[Carl]

KH and pH do not always go hand in hand do to other minerals in the water.

My suggestions are twofold

ONE is to try a KH of 100 and accept the pH that comes with this

TWO is to use 25% RO or DI water and then adjust to a KH of 150 and again accept the pH that then comes with it

BTW, I have kept Goldfish very successfully at a pH of 8.2 and did NOT chase a lower pH even though it is suggested that goldfish at generally best at around 7.8, I have not found this to be a problem when higher

BTW, great question and something I will definitely add to the Aquarium Chemistry Quick Tips Section

Also welcome to Everything Aquatic

Carl

[munter1642]

Thanks for the response, much appreciated

While we are still on chemistry I have a few other queries

Following american aquarium products website, which fills me with confidence that they know the science behind the fish and water I have converted to seachem products.

Using the seachem acid and alkaline buffers the directions for use are a little confusing. Can acid and alkaline be combined to raise kh but limit ph rises, Or are they best used individually?

I am currently making 8 litre water changes every other day equating to about 20% water change a week. When I use seachem prime it suggests dosing the quantity of new water only, however using api stress coat it suggests dosing based on the aquarium volume. There is a Significant difference in dosing here? Is this correct?

I have also followed advice and replaced my aqua one HOB zeolite medium with seachem purigen in 'the bag'. Is this correct? Can you double up and use the standard aqua one filter cartridge and the purigen bag?

Thanks

Matthew

[Carl]

Jun 3, 2013 5:33:22 GMT -5 munter1642 said:

Using the seachem acid and alkaline buffers the directions for use are a little confusing. Can acid and alkaline be combined to raise kh but limit ph rises, Or are they best used individually?

Yes, but add each separately.
The addition of both also produces CO2 for plants

See also our Aquarium Chemistry Buffer Tips section

I am currently making 8 litre water changes every other day equating to about 20% water change a week. When I use seachem prime it suggests dosing the quantity of new water only, however using api stress coat it suggests dosing based on the aquarium volume. There is a Significant difference in dosing here? Is this correct?

Either is OK, whether the amount of only the water change or the full tank size.

Generally I only add the full tank amount when the fish might be stressed and the water conditioner and its Redox Reducing properties might be helpful

See Also:
Aquarium Water Conditioners; Review, Information

I have also followed advice and replaced my aqua one HOB zeolite medium with seachem purigen in 'the bag'. Is this correct? Can you double up and use the standard aqua one filter cartridge and the purigen bag?

Thanks
Matthew

Yes, as they can compliment, however I often find that just the Purigen is needed once a tank is established
Please also note that while Purigen is a great product, if not the one of the best chemical filtration products, it can also adversely affect Redox if there is not good positive mineral ionization, so the use of Wonder Shells or similar is suggested

See also: Aquarium & Pond Filter Media, Material; Mechanical, Bio, Chemical

Carl

[munter1642]

Hello fish friends

Still having difficulty finding a reasonable KH and PH balance.

For my 100 litre (actual water) tank I have been cutting tank water with 15 litres of spring water adjusted to 7.0 PH and over 200 KHand GH. When the spring water is added the tank PH seems to drop to a PH of 7.3 then rises back to about 8.3 after 4 hours. Over the next 48 hours the tank PH stays at about 8.3 but the KH falls away at about 1 or 2 DGK per day. Once the KH is below 100 I cannot add alkaline buffer as it sends the PH up also which I don't dare do.

Wondering if something in my tank is causing the rapid reduction of KH or the increase in PH. I have two small pieces of driftwood and one terracotta pot all with Anubis on them, I also have about 10 stems of broad leaf plants (not sure what they are)

Do I need to use more spring water for water changes or is something in my tank affecting the KH/PH balance?

Thanks
Matthew

[Carl]

This tells me you have something producing copious amounts of acid; whether it be your driftwood or your terracotta pot, or both

Also not all "spring Water" is the same, better to use a known quantity such as Reverse Osmosis (RO) or Distilled (DI) water

Please Read:
www.aquarium-pond-answers.com/2006/12/how-do-fish-drink.html

I am not against the use of Spring Water, it can be excellent, but for "cutting" water it often has chemistry that can affect the results

Carl