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got a small school of Congo Tetras coming today... Time to start testing out my new blended water... with some new fish

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Magnum Man

Fish Herder
Jun 21, 2023
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Southern MN
it's been taking a long time for the nasty water in my tanks to blend out doing 5 gallons at a time RO water changes... But, I am getting closer... so hoping the Congo's will be OK...

last nights water tests after another 5 gallon RO change & 15 minutes for the tank to blend ( I always pull water from one end, & add water from the other end... the tank the Congo's are going into is still a Ph of 7.4 ( there is driftwood, & dead leaves in the tank, but the KH was so high the Ph has been stubborn to move... but initially before RO it was a Ph of 8.4... so it is starting to come down... GH is <25 & KH is still at 120, even though about 90 gallons of RO has been cycled through the 45 gallon over the last month... I have make up elements here for RO water for any tanks that may need it down the road...
They are here, and didn’t die right away, been in the tank a little over an hour and they ate already… man are they tiny… maybe an inch long… fingers crossed… I want some angels in this tank… but the Congo’s are my canaries… we’ll see if I can keep them alive first
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All the best with that Mr Mag. Lovely fish. You seem to be working your socks off with various things right now. Putting in a good shift!
This is what my mind saw when I read the title. I need some sleep.

got a small school of Congo Tetras coming today... Time to start testing out my new blender... with some new fish
Got a small pack of silver dollars in the same box… got regular, tiger stripes, and spotted… and they are tiny as well… they have a tank to themselves ( along with a big common pleco, I don’t know what else to do with)… this is the tank the Bichirs are going into this fall ( when they come in from their job in the Tilapia set up outside )… now I have to get busy growing them up… I saw one of the bichirs last night for the 1st time since I added them to the plant tank… they went in at 3 to 4 inches…. The one I saw last night was 8 to 10 inches now… never gave a thought, that the silver dollars might be small enough that they get ate… better start feeding them up on pellets…
Baby Congo’s you would need more than 4 for a smoothie
Vampire is in this same tank… came out to welcome them this morning
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Hmmm… haven’t seen him out from under the drift wood before… hope everything is ok.. he seems to be doing a “walkabout
Cycling RO gradually as you have been doing makes it hard to get a stable result. If you do not drop the KH and have it stay down, the pH will rise back some after every water change.

Without knowing more and asking a lot of Qs, my guess is there may be something in the tank which is raising the KH. If you have the proper digital test equipment I would suggest you test the RO water itself. I would want to see what the TDS have been running to get some sort of idea why the kH and thus the pH remains where it is.

While we tend to simplify all of this to make understanding easier, here is the underlying chemistry:

Acids, Bases, and the pH Scale​

The terms acid and base describe chemical characteristics of many substances that we use daily. Acidic things taste sour. Basic or alkaline things taste soapy. Strong acids are corrosive and strong bases are caustic; both can cause severe skin damage that feels like a burn. However, mild acids and bases are common and relatively harmless to us. What makes a substance acidic or basic? The following equation is a good place to start:

2 H2O ⇌ 1 H3O+ + 1 OH-

We begin with two water molecules, and move some hydrogen atoms around. One water molecule gains a hydrogen and therefore takes on a positive charge, while the other water molecule loses a hydrogen atom and therefore becomes negatively charged. H3O+ is called a hydronium ion, and it makes things acidic. OH- is called a hydroxyl ion and it makes things basic. However, in water, there is a balance between hydroniums and hydroxyls so they cancel each others' charges. Pure water is neither acidic or basic; it is neutral.

So how does something become acidic or basic? That happens when the hydroniums and the hydroxyls are out of balance. If there are more positively charged hydroniums than negatively charged hydroxyls, then the substance is acidic. If there are more negatively charged hydroxyls than positively charged hydroniums, then the substance becomes basic. pH actually stands for the "potential (or power) of hydrogen."
from https://www2.nau.edu/lrm22/lessons/acids_and_bases/acids_and_bases.html

Now, lets consider that RO units on their own do not remove Ions. And ion is anything that has a charge and in the chemical formula that is indicate by the + or = in the formula. Ions are removed from water by have a module with deionozing resin in it. This traps the Ions. When I run my water through my RO/DI system, I get water with almost 0 TDS. The reason for the almost is that when the is CO2 in water it creates carbonic acid. This acts to lower pH. So my "pure" water is not 7.0 and 0 TDS.

However, once my RO/DI goes into the tan, there are other things that can cause the anticipated result not to be what one expects. There is something else in the water which is working against the pH remaining low. The problem is in our being able to discover what that is.

So, I batch changing water based on the current tank readings at the time. I see temp., TDS and pH. I mix my water so it should produce a result of 6.0 pH and TDS in the range of 60-70 ppm (in dg 3.3 - 3.9). As the week progresses between water changes the numbers tend to rise towards 6.5 and 80 ppm. However. my TDS tend to read in 10 ppm increments. A few ppm over 60 and it will read 70 etc. I have never been able to determine exactly why this happens.

My hand held tester reads in single ppm, increments which is how I determined what the continuous monitor was doing. It lets me choose between conductivity and two TDS scales. Conductibity is the more accurate measure but I just cannot wrap my head around those tiny sailors in which they measure- aka microsiemens. So I prefer to use TDS which make a bit more sense to this old brain.

What I can say is that doing what I have for some time and you are just embarking on takes some time to get a feel for before we think we understand what is going on in our tanks. My problem is that I never took a chemistry class when in school. I switched high schools midway though and the two schools had one take chemistry in different years and so I learned no chemistry but did take physics twice. It has been a hard slog to try and learn about this stuff as a result.

The one thing I do know about all of this is that the only way I can both understand what is gpoing on and then determine what to do relies on my digital testing equipent. I tried using pH pens to test but they kept crapping out. I tried a less expensive Chinese made continuous monitor which was not very good either. I then settled on the BlueLab Guardian monitor. My model is pretty basic- no wi-fi, no connectivity, just reads the three parameters I mentioned. I do not see it on the Bluelab site but I do see it here https://www.greenhousemegastore.com/products/bluelab-guardian-monitor?variant=42701271072967
We have extremely hard alkaline water here, and the tanks were filled originally with whole house softened water… I’m intentionally trying to change it over slowly for the benefit of all the fish in those 4 tanks… they include 3-55 gallons, and 1-45 gallon right now, that were already set up with that water
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Trying this... show you where I'm at geographically... I live in southern Minnesota... right in the middle of the biggest patch of hard water in the US...

I wonder what comes after "extremely hard", maybe "unbelievably hard?". In London, UK we are also the hardest!

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