Wondering about my KH value

[An t-iasg]

As I plant my tanks more heavily than they were before, I'm wondering if my [acronym:f8b746d2cc="Carbonate Hardness"]KH[/acronym:f8b746d2cc] is going to be ok. Well, it's probably not and overnight I don't want the pH to swing. I read that you can add baking soda to raise [acronym:f8b746d2cc="Carbonate Hardness"]KH[/acronym:f8b746d2cc] without affecting pH, but the amount that I would need is something like less than 1/8 teaspoon per gallon, which is pretty hard to measure accurately. The [acronym:f8b746d2cc="Carbonate Hardness"]KH[/acronym:f8b746d2cc] is 1dKH, the [acronym:f8b746d2cc="General Hardness"]GH[/acronym:f8b746d2cc] is 4dGH, and the pH is 6.8. Add the overnight pH swing possibility and possibly the Seachem Excel's affect on pH and I'm uncertain on how to proceed.

[greenmaji]

I have absolutely no experience with the Excel product.. So Im going to go with the rest of the information you have in your post..
you are probably on target with being consered with a possible [acronym:8f06f88d8f="power head or Measure of the concentration of hydrogen ions, depending on context"]PH[/acronym:8f06f88d8f] swing.. Do you have [acronym:8f06f88d8f="Carbon dioxide"]CO2[/acronym:8f06f88d8f]? If not I would worry more about my [acronym:8f06f88d8f="Oxygen"]O2[/acronym:8f06f88d8f] levels, plant respiration and all..
The added acids from the new plants shouldnt be alot more than the acids involved in your system before they were added.. how often and how big are your water change's?
If your doing 30%+ [acronym:8f06f88d8f="Partial water change"]pwc[/acronym:8f06f88d8f]'s every other day then dont worry about it.. If you [acronym:8f06f88d8f="Partial water change"]pwc[/acronym:8f06f88d8f]'s are fewer and less % then I would suggest that you check your [acronym:8f06f88d8f="power head or Measure of the concentration of hydrogen ions, depending on context"]PH[/acronym:8f06f88d8f] an hour before the lights come back on and see if there how much the [acronym:8f06f88d8f="power head or Measure of the concentration of hydrogen ions, depending on context"]PH[/acronym:8f06f88d8f] is effected..
My only concern is the amount of new plants in your tank you have added alot more than you had but from my understanding the acids added by plants have less of an effect on [acronym:8f06f88d8f="power head or Measure of the concentration of hydrogen ions, depending on context"]PH[/acronym:8f06f88d8f] swings then the nitrification acids..

[An t-iasg]

More info: the values above were from the tank. I use half tap and half [acronym:88aeb52028="Reverse osmosis"]RO[/acronym:88aeb52028].

The plants right now are still in critter keepers, in tap water. I tested the pH of the water in the critter keepers: pH is 7.2 in one and 7.4 in another, down from 7.8. So it seems like the pH falls with the addition of the plants, but the fish are used to the mix of tap and [acronym:88aeb52028="Reverse osmosis"]RO[/acronym:88aeb52028]. Hmmm. I'll test the pH of the critter keepers again in the morning before I turn the lights on. Since I'm not injecting [acronym:88aeb52028="Carbon dioxide"]CO2[/acronym:88aeb52028], will the morning value matter, or be any different from the evening value? It should change, right, since the plants take in [acronym:88aeb52028="Oxygen"]O2[/acronym:88aeb52028] at night? Yes, this is making me batty

[greenmaji]

On the other hand you can always under dose the baking soda! [acronym:4a5747b76c="Rolling on the floor laughing"]ROFL[/acronym:4a5747b76c]

[greenmaji]

In that case why dont you slowly acclimate the fish to a lower dosage of [acronym:23ae24398e="Reverse osmosis"]RO[/acronym:23ae24398e]..?

[greenmaji]

since the plants are taking [acronym:b6827eaab2="Oxygen"]O2[/acronym:b6827eaab2] in at night my best theory would be that the [acronym:b6827eaab2="power head or Measure of the concentration of hydrogen ions, depending on context"]PH[/acronym:b6827eaab2] would be slightly lower.. more [acronym:b6827eaab2="Carbon dioxide"]CO2[/acronym:b6827eaab2] in the water from it not being consumed.. make any sense? the [acronym:b6827eaab2="Carbon dioxide"]CO2[/acronym:b6827eaab2] should only be 3-4ppm at most without injection so the swing shouldnt be that significant..

[An t-iasg]

Originally Posted by greenmagi

In that case why dont you slowly acclimate the fish to a lower dosage of [acronym:658f1fb77e="Reverse osmosis"]RO[/acronym:658f1fb77e]..?

Yes, I considered that too. That may be the easiest in the long run, and it could be done slowly.

Originally Posted by greenmagi

the [acronym:658f1fb77e="Carbon dioxide"]CO2[/acronym:658f1fb77e] should only be 3-4ppm at most without injection so the swing shouldnt be that significant..

I wondered about that too -- since I don't inject [acronym:658f1fb77e="Carbon dioxide"]CO2[/acronym:658f1fb77e], maybe I'm worrying a bit for nothing...we'll see what my morining pH is.

[greenmaji]

Your situation will defiantly proof the theory..

[Steve Hampton]

Originally Posted by An t-iasg

As I plant my tanks more heavily than they were before, I'm wondering if my [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] is going to be ok. Well, it's probably not and overnight I don't want the pH to swing.

I wouldn't be as concerned about an overnight swing as I would about having a dramatic drop to a very low pH that stays low.

I read that you can add baking soda to raise [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] without affecting pH,

Actually you can't. If you add baking soda (sodium bicarbonate) you have increased the [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] or bicarbonate buffer and the pH will rise...the amount of the rise is dependant on the increase in the [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066], but if you increase your [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] from 1 to 3 you will see a rise in pH too. You could add a very small amount of baking soda and not be able to see the rise in pH with a pH test kit, though it would show with a good pH meter. Adding baking soda will not increase the [acronym:def49f5066="General Hardness"]GH[/acronym:def49f5066] reading...although the [acronym:def49f5066="Total Dissolved Solids"]TDS[/acronym:def49f5066] has increased. For some soft water fish the increase in sodium is worse than an increase in calcium and/or magnesium (the hard water constituents). But for most fish the slight elevation in sodium is unproblematic.

Seachem Excel's affect on pH and I'm uncertain on how to proceed.

Excel shouldn't have any effect on pH.

Some important points to remember:

[acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] concentration in an aquarium doesn't depend on the other things dissolved in your water. (many folks think [acronym:def49f5066="Oxygen"]O2[/acronym:def49f5066] levels and [acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] levels are linked...they are independant of each other)

[acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] is the amount of bicarbonate

pH is always set by those two ([acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] and [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066])

A stable pH depends on both being present in reasonably comparable quantities.

Plants CAN'T remove [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] if the [acronym:def49f5066="General Hardness"]GH[/acronym:def49f5066] is low. When plants do remove [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] the pH becomes very high (8 to 10) and a deposit of calcium carbonate forms (biogenic decalcification) and both [acronym:def49f5066="General Hardness"]GH[/acronym:def49f5066] and [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] drop.

So, generally speaking, plants during photosynthesis will remove [acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] from the aquarium water, removing [acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] will cause the pH to increase ([acronym:def49f5066="Carbon dioxide"]CO2[/acronym:def49f5066] forms carbonic acid...a pH lowering acid uneffected by the buffering mechanics that [acronym:def49f5066="Carbonate Hardness"]KH[/acronym:def49f5066] has on other acids). Fish respire ammonia/ammonium from their gills, combined with solid wastes being broken down by bacteria an you have lots of nitrification depending on the number and size of the fish and the amount and type of fish food given. Meaning, it's fairly easy to overwhelm a low buffer with the acids produced within the tank. Healthy plants generally help remove acid cause issues within a tank...but new plants that may not be healthy can and do exacerbates the nitrification problems.

[malkore]

I can second Steve's comment that Excel doesn't alter pH whatsoever. It does seem to decrease [acronym:975f9d36d0="Oxygen"]O2[/acronym:975f9d36d0] levels in the water by no more than 1ppm, and within a couple hours it's gone.
This of course assumes that the Excel doesn't just mess up an [acronym:975f9d36d0="Oxygen"]O2[/acronym:975f9d36d0] test kit