Low KH / pH OK --- how to proceed?

[Mmathis]

My indoor 20 gal. tank has just become a QT for some new goldfish I ordered. And since adding the fish, I've done nothing with the water, same filtration, 2 air stones -- no meds., no salt, no additives (other than those to remove chorine & chloramine from the source water).

I just checked the water.
The pH is OK [and is consistent with past readings from this tank], but the KH didn't even measure. I'll add some crushed oyster shells, but since the pH is essentially OK for the moment, do I need to do anything else, like add baking soda? Or is baking soda only for when the pH is low as well?

Also, I know to take things slowly, but how much, how fast?

pH 7.8 (source water is usually in the low 8 range)
KH -- the water in the tube didn't change to blue when I added the first drop of reagent, but turned yellow, which is the "end" result --

Ammonia <0.25 (slight color change, but somewhere between 0.0 & 0.25ppm)
Nitrite - 0
Nitrate - 0

 

[crsublette]

All that matters is that the pH stays stable, but I would do your best to have your quarantine tank water to match the water chemistry of their final destination such as their pond. So, I would primarily use your pond's, or "final destination", water in the QT. Also, I would add a companion fish from your "final destination" to your QT. This is due to the idiom called, "old pond syndrome".


As all ponds age, they create their own "ecosystem", which will contain various concentrations of contanimants and other unknown microorganisms and water chemistry that other ponds or other water will not have. The fish already in the pond has adapted to the "old pond" conditions. However, this does not mean a new fish will instantly adapt and remain healthy to the "old pond" conditions.

If the new fish struggles adapting to the new pond's "ecosystem" and water chemistry, then this stresses the fish, which inevitably lowers its immune system and osmoregulatory abilities, and then this leaves the initially "disease free, parasite free" fish extremely susceptible to infections from very basic microorganisms that healthy fish easily overcome and the "old" fish in the pond easily overcome as well.

Irrelevant from where the fish came from, you should still quarantine the new fish in a seperate tank with "old pond" water, not with a chemical bath, and the tank preferably with another fish from the "old pond". If any problems should arise, then it will be easier to treat the new fish in the smaller quarantine tank environment with the proper treatments.


To answer your KH/PH question, I would strictly use the water from your pond, or the "final destination" if it is not a pond. So, I imagine this might possibly involve a higher KH value.

 

[dieselplower]

Charles is your advice then to add nothing? I wouldnt add anything. I don't know why so many people always want to add things. However, I have very hard well water, which could mean I just don't understand the issue, since I've never had a need to add anything.

 

[crsublette]

If by "add nothing" you are referencing salt or other products in the QT, then correct I would "add nothing".

Although, if the new fish are acting frantic or something similar, then it is quite fine to increase the salinity to 0.10~0.15%, as long as there are no fully submerged aquatic plants in the QT. The salinity increase from sodium will simply help the fish breath better and increase their slime coat, that might have been lost due to the stress, while they're adapting to the various microorganisms in the "old pond" water.

I think folk add things due to the "do something" mental ailment.

 

[Mmathis]

I was thinking in terms of a pH crash, if the KH is so low that it doesn't register.

 

[crsublette]

I always thought of a "pH crash" as a quite huge swing in pH and so then KH acts as a type of tension controller or pillow to soften or reduce this swing. A pH crash only registers when the KH is "relatively" low. You have to test the fish tank water multiple times throughout the day to determine if there is a "pH crash". So, eventually, as ammonia accumulates and is processed by the filter and as the fish expel carbon dioxide, a pH crash will soon be inevitable unless there is a constant flow through of water or constant water changes.

If you want to increase the KH, then it should be done in 1 dKH (or 17.898ppm) increments every 24 hours. So, for 20 gallons, after using the baking soda alkalinity calculator, then this would require 0.067 ounces (or 1.89 grams) of baking soda. A leveled, half TEAspoon of baking soda is 2.4grams. So, dose the water, once every 24 hours, with a little less than a leveled, half teaspoon of baking soda or use a gram scale. A half leveled teaspoon might be ok.

Since it takes a moment for the powder to dissolve and you do not want the fish to instantly ingest the baking soda powder, then, first, I would significantly agitate this small amount of baking soda in a small sealed container with fish tank water to make sure the baking soda is all dissolved. Then, add this water to the tank. Do this once every 24 hours until you reach the KH level you desire.

 

[Mmathis]

After I got my noonish readings today [original post], I added some crushed oyster shells in the flow of one of the air stones. Then, after [just now] reading your [Charles'] last note, I did another partial-check:

Ammonia = 0ppm [down from a trace]
pH = 7.2 [down from 7.8, but since I haven't been doing regular readings throughout the day prior to this, this could be normal....]
KH = around 36 [at least the water turned blue this time...]

I'll just monitor frequently from here. At least I'm having some nice "bonding" time with the new fish, LOL!