pH Instability

[drayman86]

Here’s one for the chemists, or anyone else with a good handle on acid/base chemistry:

I’m treating pretty high pH municipal water with peat moss. Here’s the analysis from my water board of what’s coming out of my tap:

http://www.lbwl.com/communityimpact_WaterQuality.asp

(Please scroll down to bottom of page for anaysis results.)

As we can see, pretty soft, pretty low buffering capacity, but a high pH. (I’ve verified the pH with a quality pH meter.)

I can filter the water through peat moss in a canister filter, and have been able to get a final pH of the treated water of 6.8. All of the buffering capacity of the feedwater has been exhausted, as the final pH remains stable over time in the treatment tank after peat moss filtering has been discontinued.

I’ve set up two grow out tanks, both 29 gals. They are bare tanks with a Hydro IV sponge filter and heater. The tanks have been set up for just over 8 days. I inoculated the tank with a commercial pelletized bacteria culture (Actizyme), and then added some standard goldfish to provide waste and a food source for the bacteria. Here’s the Actizyme website if you’re interested:

http://www.ntlabs.co.uk/ntlabsframe.htm?koicare.htm~main

Here’s the QUESTION: the pH in the tank keeps bouncing up and stabilizing at about 7.5. Why? A 25-30% water change with treated water knocks the pH back to around 7.0, but within 12 hours is rises again to about 7.5. Here’s my thoughts/hypothesis:

1. Something in the Actizyme, also listed as a sludge remover, has added excess alkalinity to the tank.
2. The tank water contains no detectable levels of either ammonia or nitrite. This is rather odd for a “new” tank with fish, no? Perhaps the nitrite is combining with the excess protons to form nitrous acid in solution?

NO2- + H+ ---- > HNO2

Goldfish in grow out tanks are being fed lightly with standard flake food.

Any thoughts or opinions would be greatly appreciated as to why the pH keeps bouncing up in these new tanks. I realize I may be a bit fussy on this point, but I want to get a VERY good handle on this pH thing before introducing discus to the system

[brewmaster15]

HI and welcome to SimplyDiscus!


Can we take a step back... lets look at your water from the start, can you take a measure of your waters pH directly from the tap? Then aerate it for 12-24 hours and re-measure the pH? additionally... IK would take on the 2 tanks, and do 100% water change and see what happens without the actizyme added.


Its possible that the actizyme is adding buffering, as bacteria that break down wastes thrive in alkaline water..it would be smart for the manufacturer to add it to the mix.


-al

[drayman86]

Al:

Thanks for the welcome and the reply! I was very pleased to find such a great site with a message board containing much needed information.

I'll do just what you suggest, track the pH, and post the results in about 36-48 hours.

Of course, I'd appreciate suggestions and opinions from other members as well. Thanks again to all!

Greg

[Carol_Roberts]

By the way, you don't need to lower pH for growing out juvenile discus. Do run the tests to find out what your water is from the tap and the pH of a glass of water that has set on the counter overnight. My water colmes out of the tap at 6.8 and my pH stabilizes at 7.8 after aeration. Juveniles will grow jsut fine in 7.8

[raglanroad]

2 thoughts:
try testing water before and after actizyme, in your prepared water. It might directly tell you that the actizyme altered the water.If it does not alter the water,
try removing the peat after lowering the pH. it may contain all the carbonate hardness bound up in the peat, which could possibly be the cause.

[drayman86]

Al (aka Brewmaster 15):

I took your suggestion and aerated my tap water in the 55 gallon treatment drum. Here's the time vs. pH results listed in order of date, time, and pH:

5-10-05 - - - - 5:45 pm - - - - 9.38 (tap water)

5-11-05 - - - - 7:00 am - - - - 8.15

5-11-05 - - - - 5:02 pm - - - - 7.90

5-12-05 - - - - 6:00 am - - - - 7.90

5-12-05 - - - - 5:00 pm - - - - 7.90

Great idea! Apparently (from what I can gather through background research), the tap water wasn't saturated with CO2. Aeration cuased additional CO2 to be dissolved in the water, thus forming carbonic acid (H2CO3), which then dissociated into bicarbonate (HCO3-) and carbonate (CO3--) until equilibrium in the system was reached. Carol seems to have had similar results with her well water going from about 6.9 up to around 7.8.

Thanks again for the suggestion, Al!

[raglanroad]

Now I'm confused. There are a couple of things here that don't fit together.

Carol's pH stabilizes at a higher number than the tap. This is because the co2, dissolved into carbonic acid, will eventually be released out of the water by aeration as co2. So her pH RISES to stable position.

Supposing you are correct that your tap contains little co2, and by aeration,you are injecting co2, not removing it. Your pH should then stabilizes at a LOWER pH.

Why then should it bounce back up? Losing your co2 again?

This is why I think the peat residue may play a role ( it may be having it's residues change from carbonates to bi-carbonates?). I always remove peat residue before addition to my tank, I condition the water in a separate container, and let it settle well, and decant the top water, leaving behind the muck. Then I filter the peat water before adding to tank.

You possibly could calculate the effect of aeration on your water, because air has a known percentage co2. But It may be easier to do practical tests, like watching the peat reactions using different methods.Or testing the actizyme for a pH shift with your peat water, and tapwater, after stabilization.

There is a paradoxical reaction with carbonates that takes place under certain conditions, where the addition of bicarbonates will LOWER pH, by forming crystals on the surface of existing carbonates,which are the more active components at high pH, for a short time, then releasing them again. I don't think this is happening, though, as your GH KH is not high. Perhaps you have a high TDS, though, which is not being measured by your GH test.

After looking at your water report, it seems that although they give a low GH value, it has been softened ( substituting other ions?). Note that you may have conductivity as high as 750. A wild fluctuation from 250. I call that osmotic stress in a big way. RO time.

[drayman86]

Hey Raglanroad:

Thanks for taking the time for such a detailed response. I find myself coming up with more questions than answers when it comes to the background research I'm doing on acid/base water chemistry and trying to understand what's happening in the system.

I'm likely guilty of carrying this whole thing too far, although once I get on a "research roll" (particularly with the science stuff), I tend to push to past the sensible limit.

Think I'll take a cue from Al and step back from all this. Right now, it's enough for me to know that a good 24 aeration in my treatment barrel will stabilize the pH of my tap water to about 7.9. I'll continue with peat treatment from that point. (My only use of the Actizyme pellets was adding about 2-3 grams to each of my 29 gallon grow-outs at the beginning. I don't use Actizyme in my treatment system.)

I'm going to do a 100% water change on each grow out tank with peat-treated water after rinsing each sponge filter to remove any residual Actizyme additives.

Water Treatment Set-Up

Here's the treatment set-up I have. Would appreciate your thoughts:

It consists of a 55 gallon food-grade plastic barrel. I use a Fluval 404 with plain peat moss (no additives, etc.). I've been running the water through the treatment system immediately after it comes out of the tap. I'm going to do the next batch with thoroughly aerated water that has been pH stabilized.

Q: What type of post-filtration of the water so you do? What filter system/media do you do?

Q: What about the tannin stain of the water? Have you found any way to clarify it?

I have noticed that, as you've stated, the "muck" settles to the bottom of the treatment barrel in about 24-36 hours.

I'll try it and see how it goes. Thanks again.

Greg

[Jimjamba]

Hi there

I found that making sure the pH was exactly as you wanted was no easy process. Although, I found some of the Aquarium Pharmaceuticals products for pH very good.

http://aquariumpharm.com/aqwater.html

It will stabilise your pH to how you want it until you find the best way to remedy the water in your area, and give you more time to get your head round all the science areas.
It is an easy way out and does have it's drawbacks, such as keeping live plants, which isn't always easy with it due to the phosphate buffer.
I wouldn't recommend it forever but I found it a useful interim whilst I found my feet.

Good Luck,

James

[raglanroad]

I added a little cichlid buffer to my african tank and all the plants croaked.

Drayman, to get the peat to behave,(it's better to contain the stuff in a stocking so it never all gets free in the barrel, actually) I found it good to let the peat water it settle , with no aeration, then decant the top for use. Then I filter the decanted liquid by pouring it through a filter made by really compacted filter floss, in a container with holes in the bottom. You may run it through several times. This leaves you with very few particles. It is the particles that give the trouble, I find. For the left-over slight tinge of colour, many think it is desirable , or even helpful to the fish, or cuts down algae growth. I found that a sponge filter with a powerhead gets the last bits of particle, and there is practically no stain left in the water. It was all such a chore, though, I only did that for special purpose tanks, like if you want to breed some difficult fish, or if you have a small set-up. There must be a way to do it in a more intelligent manner.
The Germans used the peat-bomb method, a drum packed with peat, and pressure the water through it. You might research that.
German long-strand peat, considered by some the finest bio-filter bed possible, is available in Home Depot, in a different place than the regular sphagnum, at $4 a bag- much better than the pet store price for the peat plates. It has less strength for acidity, but it has been used in many instances for success with difficult fish. Use it as a medium, not an acidifier. Check for additives as usual. So to answer, I think the best filtration is a sump with long-strand peat bed, for the ingredients used by softwater fish. Followed by 2 chambers of plants, to remove ammonium, each run for 8 hrs of light, and plants in the tank for the daytime...plants are the perfect filter, if there is such a thing. There are many considerations: quarantine, show, breeding, breeding prep, etc. I'll do the planted sump when I have my life in perfect order. : )

[drayman86]

Hey raglanroad:

Thanks again for your helpful posts.

I think I'm getting closer to a more stable peat treatment system, i.e consistent, reliable results in terms of post-treatment water parameters. Been working with the Fluval 404 and baskets and polyester filter fiber. Took a cue from Carol's suggestion in using carwash sponges for power filter pre-filters, and have used same sponges in Fluval baskets post-peat to remove finer suspended paritculates.

Anyway, I part of my problem (I believe) was a dumb thing....wasn't treating the feedwater going into the peat treatment barrel for chloramine. Duh! After testing my tapwater and finding 0.5 - 1.0 ppm ammonia/ammonium, I'm checking the message board posts on chloramine, chloramine treatment products, and the chlormaine/ammonia/ammonium relationship.

Thanks to all the posts here and the helpful responses I've received, I've learned a great deal! Much thanks to all you experienced members for sharing your knowledge...this message board is THE best place for learning about discus. :thumbsup:

Greg

[drayman86]

After a lot of experimentation, I got my water treatment and delivery system installed. See the pics here:

http://forum.simplydiscus.com//showthread.php?t=43661

After removing chloramines, I can modify the water essentially any way I'd like. Currently using peat; can always add RO later.