Questions on adding chems at water change

[ORANGEPEEL]

Did a water change this past weekend. Our water source is very clear well water and I needed to increase the PH and Alk levels, then also add Dichlor.
My method is to add the PH increaser (Sodium Carbonate) first, then add the Dichlor.
I predilute the chems. individually, by dipping a small plastic bucket into the tub water, add the chems. to the bucket, stir, then into the tub.
While doing this, a couple of questions cross my mind: First should I adjust the PH and Alk before adding the Dichlor or vice-versa ?
Second, does the temperature of the water have any effect on the readings for the chems?
The well water was at 49 F, and I put the chems. in at that temp., then let the full jets run for about 5 minutes before testing and further additions. proper levels were eventually achieved. I always try to start lower then work up to the proper levels.
Also,I believe I have read prior posts that Bicarbonate of Soda (Baking Soda) can be used as an alternative to Sodium Carbonate is that correct?
Thanks in advance for your replies.

[windsurfdog]

Did a water change this past weekend. Our water source is very clear well water and I needed to increase the PH and Alk levels, then also add Dichlor.
My method is to add the PH increaser (Sodium Carbonate) first, then add the Dichlor.
I predilute the chems. individually, by dipping a small plastic bucket into the tub water, add the chems. to the bucket, stir, then into the tub.
While doing this, a couple of questions cross my mind: First should I adjust the PH and Alk before adding the Dichlor or vice-versa ?
Second, does the temperature of the water have any effect on the readings for the chems?
The well water was at 49 F, and I put the chems. in at that temp., then let the full jets run for about 5 minutes before testing and further additions. proper levels were eventually achieved. I always try to start lower then work up to the proper levels.
Also,I believe I have read prior posts that Bicarbonate of Soda (Baking Soda) can be used as an alternative to Sodium Carbonate is that correct?
Thanks in advance for your replies.

First, understand that sodium bicarbonate (baking soda) and sodium carbonate (soda ash) are not entirely interchangable though they are very similar.  Both will affect TA and pH but baking soda will affect TA more than pH where soda ash will affect pH more than TA.

After a water change, I usually just put a couple of tsp. of dichlor in while the water is heating and then jump in after the water gets to temp.  I certainly like the feel of fresh water with as few chems in it as possible...at least for a couple of soaks.  But if you want to add baking soda, soda ash or, even possibly dry acid if your pH is way high, then adding them together or separately along with dichlor would be just fine.

The water temp won't have a big effect on the chem readings but aerating the water will push the pH up.

HTH... 8-)

[txwillie]

The water temp won't have a big effect on the chem readings but aerating the water will push the pH up.

Why is that?

[windsurfdog]

tx,

I wish I knew exactly why but I don't.  I know I've read several discussions on this board about it but either I wasn't convinced or I just plain forgot...probably the latter.  Either way, I know it is a phenomenon that I experience at each water change.  The water out of my tap is pH 7.4 or so...pretty darn good.  After filling and running the pumps...adding agitation and aeration...the pH measures out just over 8.  I've seen it happen each time so I'm confident that it is consistent and reproducable...I just don't know the chemistry behind it.  I usually don't adjust down for a week or two...those first two weeks are absolutely enjoyable with little but dichlor added to the water.  After that I gradually adjust down with dry acid shooting for 7.6-7.8.  Then I let the dichlor and/or MPS bring it on down from there.  Eventually, I'll have to add soda ash to bring it back up some but that's usually 2.5 months or so into the water change.  Works for me, anyways...YMMV.   8-)