Water chemistry again

[joe23455]

Hi
I have a question/situation with a new setup regarding water chemistry and adjusting it into a range "I think" I want based on my limited experience and reading. I will Describe my goal, my setup and short history and see where we can go from here. I have attached an Excel sheet with the details.

Goal
I want a healthy, planted tank with some easy fish that my kids can enjoy that is reasonably well buffered (with respect to pH and a pH around neutral or slightly acidic and increasing the hardness to ~80mg/l). The problem I am having :We have VERY soft water here in Vancouver ~1.5 dKH with TETRA kit or <40 mg/l with Nutrafin kit GH <40 mg/l. The pH is however persisting around 7.5 despite some mild intervention to lower it. Filtering Peat for 5 days-I like the darker color of the water but no significant change in pH. Then I tried over a couple of days to add pH down with little effect. It seems like I should have little buffering capacity but the pH ~7.5 persists. (see attached file). Why is the pH not coming down under these efforts.

Regarding my break-in cycle ammonia (kept under 0.6 mg/l)and Nitrite (<0.1 mg/l) seem well under control testing daily with a Nutrafin kit. I have used water conditioners, Cycle and Waste control amendments from Hagen as recommended.

Santa Started tank on the 21st Dec.
Setup and history is described in detail in an attached MS Excel file
Tank 16 Gallons; Glow-light cover with 15W fluorescent: heated to 21C/70F.: 2.5 to 3 inches of 3-4mm gravel with 25g/gallon of Laterite gravel mixed in to the bottom half. Floramat CO2. Piece of well cleaned and boiled Ironwood root. External filtration of with activated charcoal plus mechanical foam filtration.

I have 8 small plantings in the aquarium...basic stuff see attached.

I have 7 White Clouds and 4 bronze catfish all seem happy.

Any thoughts would be appreciated.
Cheers
Joe

 

[TankGirl]

Welcome to AA, Joe!!

Sounds like you are well informed and ready to go - I'd not worry so much about lowering the pH necessarily, the fish you are keeping are well adapted to a wide range of water parameters, and provided the tank is now cycled all you'll need to do is weekly water changes to keep things hunky dory.

I'd definitely raise the temp - 21 is way too cool for tropicals (the white clouds are fine with this temp, but not the cory cats or the plants) and they will not do well long-term. Shoot for 26C. I keep my white clouds, several generations, in a warm tropical tank.

You can quite easily buffer your water with the use of crushed coral in your filter, but this size tank might not permit much playing around with filter media. I would be very careful with that Floramat CO2, perhaps even discontinue it for now, until we get a handle on your buffering capacity. Have you measured KH? This is a small tank and your low lighting (~1 wpg) does not require CO2 at all. Stick with low light plants and you will be in fine shape.

I do not see an attachment, so forgive me if my questions or comments seem redundant!

 

[FancyGuppyGuy]

hmmm... perhaps something in the tank rocks, gravel, shells. wood. etc ??? is bringing your ph up? Have you tried lowering the ph in a glass of water then testing it in a day?

Also tap water PH will rise with aireation over a day when the CO2 is released from the water.

Try taking some water let it aireate for a day then test the ph.

Could be your real ph is 7.5 ???

 

[joe23455]

water chemistry redux

Thanks TG and Fgg,
Yes I did check tap water separately and the pH did adjust.
I Have measured GH and KH many times and really have very soft water. I have attempted to attach Excel sheet with data again. I really appreciate the advice that the fish can survive with this pH but am interested in some Harlequin, Xiphophorus maculatus or some Priestella tetras PRISTELLA MAXILLARIS which also like low pH. Perhaps the problem is more with me! I do not understand why I cant lower the pH of very soft water that should have very little buffering capacity. I have also read that if the water is very soft there is the possibility of an acid crash. Is this risk real?

The site will not let me attach a document with xls extension. I have generated a jpeg of the spreadsheet that I hope you can read.
Cheers
Joe

 

[BrianNY]

Occasionally I'll get a reading from a reagent test that doesn't make sense to me. Before I believe the reading, I'll buy another test kit to double check the result. They do have a shelf life.

Unbuffered water WILL eventually have a pH crash. I've actually seen it drop below 4. 8O Do yourself a favor and read the article on pH stability in the Articles section. This will help you understand why a stable pH is more important than some magic number.

HTH

 

[joe23455]

Hi,
Thanks for the suggestion but I have many years of molecular lab experience and I have gone through that thought process so I am using 2 pH kits and 2 KH kits from different manufacturers. I will look at the article on this site. I have read a number of articles on pH, CO2 and water hardness etc. and understand them. They just do not seem to fit exactly with my specific observations so I must be missing something critical in the "theory".

Another attempt at adding my aquarium history data. This site is very restrictive on attachments. This is a jpeg of a table.

Thanks all
Joe

 

[jsoong]

If I understand correctly, you have soft water with low Gh & KH, but persistant high pH.

Now, if you only have a carbonate/bicarbonate buffered system, at atmospheric CO2, your pH should be close to 7.0 with such a low KH. This is by the Henderson-Hasselbach equation, assuming that KH = HCO3 level.

Since the pH isn't as predicted, I will have to conclude that the water have a second buffer that is keeping the pH up, and the test kits are mot measuring this buffer as KH. This may be something added by your water co. EPCOR in Edmonton posts their water chemistry on the web, and it states that to reduce corrosion in pipes, the pH is maintained at 7.8 with added [acronym="Sodium hydroxide"]NaOH[/acronym]. Since we have fairly high HCO3 levels already, there is not much doctoring needed. I wonder if in Vancouver, to maintain the high pH in soft water, that they add some other buffer, & that can account for your observations.

You might dig aroung Vancouver's water Co to see if this is true. Also, if you have access to real lab equipment, you can measure HCO3 levels <I can do that with a blood gas machine>. If HCO3 level is low & pH is high, a second buffer must be present.

 

[Menagerie]

Since I am only a biologist and have forgotten all my chemistry knowledge, I will tackle a different subject.

I have used water conditioners, Cycle and Waste control amendments from Hagen as recommended.

STOP. The only thing you need to add to you aquarium is water conditioner. The only way to really get rid of watse is to remove it with a gravel vacuum. With a planted tank, nitrates should not be an issue. I have yet to hear anyone give rave reviews for Cycle. Discontinue the excess chemicals, you'll save money and your tank will be healthier for it

 

[FancyGuppyGuy]

I agree forgot the other additives make it as simple as possible and less can go wrong with your water.

 

[joe23455]

Thanks,
I will go with that advice it is more to my liking. I am still trying to track down the pH -buffer issue.

Joe

 

[FancyGuppyGuy]

Well I hope you do figure out what your doing Theres got to be an answer some where!!

 

[joe23455]

picture

Hi,
While I am working on my remedial forensic chemistry here is a picture of the tank. Could the rocks be the issue or would anything dissolving off them increase the GH which I do not detect.
Cheers
Joe

 

[TankGirl]

Don't see the pic, sorry, Joe!

Rocks and substrate can definitely impact things, but not always in a huge way. Do you have an idea of what the rocks are?

Feel free to PM fishfreek or reefrunner and they will be happy to help you attach whatever you need to.

Let me also interject that the rasboras and tetras you propose are almost definitely bred in harder, more alkaline water than they would have in the wild, so I do not at all suspect you will have one bit of trouble keeping them. Please forgive me if you are obtaining wild-caught specimens. I mention this for the benefit of others reading this thread who might think their fish choices are more restricted than they are.

Also, as tanks age, natural acidification will tend to soften the water and lower the pH, but this takes a year or more.

 

[joe23455]

captive bread

I just assume that they are from a captive breeding program. I guess I should ask and use only captives. The picture is the correct size I am not sure why it did not attach. Tt any rate I believe it is in my profile
or here is a link. The beach rocks are in the front.

http://www.aquariumadvice.com/photopost/showphoto.php?photo=6602
Cheers
Joe

 

[jsoong]

Problem rocks for aquarium usually increase Ca & HCO3 or CO3, all should be detectable with standard test kit. The rocks you have looked like rainbow river rocks I have in my tank (except for the speckled one). These never gave me trouble although my pH is 7.8 so not much CaCO3 will dissolve into the water even if I have limestone.

Anyway, I can't imagine a few small rocks will give that big of a water chemestry change in so short a time. People with problem rocks usu. have a tank full.

BTW, those numbers you posted, they are your tap water's right? If your tap water parameters are the same as your tank's, chances are that nothing in the tank is changing things.

 

[TankGirl]

Very nice tank, btw - love that swahala wood!

 

[joe23455]

rephrasing chemistry solution/problem

Hi,
The rocks are from a local beach that is nothing but rocks of the type you see in the photo, perhaps a km long of beach. You can just select the colors you want. I washed them well.

The numbers in the table are those in the tank. Out of the tap the hardness is the same as the numbers at the top of the table. The pH out of the tap is 6.7 which is what the GVRD Water Department says it should be. I did look at their water analysis and there is simply not a lot in our water other than H2O. Looking at the tank it seems that the only thing in the tank with sufficient mass that, was in from the beginning, and could have such an effect is the sand/gravel in the bottom. This did come from the aquarium store in sealed bags. It did take many water washes to get it to run clear before I put it in. It does look like fairly “inert” with lots of quartz etc.

Perhaps if I rephrase this issue from a problem to a solution I am after.

Water out of my tap is pH 6.7: GH is 20mg/l: KH is ~ 40 mg/L or 1.5 dKH. Really soft water.
For what ever reason pH in tank is 7.4 and still same softness.

To have a stable pH range all I read is that I need to first increase GH to approximately > 80 mg/L (still in the soft range) and the KH will move to a new range. I have some R/O Right (to increase general hardness) and pH stable (nearly neutral) both from KENT. What experience do people have with increasing hardness with these or similar products. It seems that most people have the opposite problem.
It seems like I should not concern myself about the pH but the stability even though the plants and fish I have prefer more acidic conditions. Stability comes from buffering capacity (not present in the tap water) so I must make amendments. So what is the safest way to go about this?

Cheers
Joe

 

[jsoong]

I misunderstood your problem. I thought the pH was 7.6 out of your tap & persists at 7.4 in your tank ....

Now, the pH of 6.7 out of the tap is consistent with your KH & GH number. So I don't think your water out of the tap is doctored, nor is there strange buffers in your tap.

Now you have added R/O Right & pH Stable to the tap water. These are the source of the secondary buffers I was talking about. I have not used any of the products, so I may be wrong in this. From a quick browse of the product description, these buffers should be measurable with test kit. The pH Stable <salts of carbolic acid> sounds like bicarbonates (baking soda) to me, and this should be measurable by the KH test. I am at a lost as to why your pH had gone up but the KH & GH had not.

To test the effect of the added buffers vs something in the tank, I would do this experiment. Measure your tap water parameters. Let the water sit 24 hrs & repeat. Then add the R/O right & pH Stable (same proportion as you have in the tank) & repeat tests. Finally, compare that with the tank's numbers. How the number changes may give a clue as to what is going on.

From what I've read, the most fool proof way to increase KH is to add CaCO3, in the form of crushed coral, limestone, oyster shells, etc. This however, will increase your pH, which you may or may not want.... A lot of people will increase the KH this way then bring pH down with CO2 injection.

People like BrianNY who use R/O water for discus will have far more experience doctoring the water with additives like pH Stable. Your might want to pm him directly.

 

[joe23455]

jsoong,
Thanks for your input. I will do an experiment like you suggest. I do not want to do anything that increases the pH, so I will keep that in mind.

Controlling with CO2 seems a bit "dynamic" to me.
Will report back.
Cheers
Joe

 

[BrianNY]

Actually jsoong I don't use any additives. I mix tap and RO water until I get a TDS reading of about 100. This is only for fry tanks with daily water change. I use cc to buffer all of my tanks because the KH from my tap is less than 1 dh. So, I end up with a KH of 6 and a pH of 7.8 (approx). The discus are well acclimated to this pH and spawn in this water. SO, IMO, all that's been written about a perfect pH is utter nonsense. Stable pH is all an aquarist needs.

HTH