Dosing twopart at the same time?

[apexi]

I have just setup two peristaltic pumps (Drew's Doser) on digital timers and was wondering is it OK to drip both the calcium and alkalinity at the same time, so long as it is dripped into different areas of the sump?

OR do they have to be added separately (ie/dose all the calcium first and then the alkalinity) and if so, what is the reasoning behind this? Is it better to dose one part or the other at different times of the day as well?

THANKS.

[Pbrown3701]

it's better to dose at different times. I have mine set up to dose alk in the am (to help bring pH up) and then dose Ca 12 hours later.

If you must dose at the same time, then be sure to dose as far away from each other as possible and very slowly

[mrpenguin]

what would happen if you do dose at the same time ??

[Bonebrake]

If you're adding it via peristaltic pumps you are adding a small volume very slowly and you can add both at the same time in practically the same area so long as there is high flow. It will diffuse and cause no problems whatsoever.

[bertoni]

Dosing them at the same time is fine. I did that regularly for years, in a mass dose. It's useful when dosing larger quantities to let the first solution mix into the system well before adding the second. Your setup should be okay as long as the sump gets enough flow.

[eskymick]

I dose both at the same time ... in different parts of the sump.
It works perfectly.

You might want to make sure that the alk solution drips in the area of the sump with the most flow (perhaps in the area where the tank water enters the sump).

[jdieck]

<a href=showthread.php?s=&postid=13128130#post13128130 target=_blank>Originally posted</a> by mrpenguin
what would happen if you do dose at the same time ??
Usually if using the recipe 1 which increases PH, the PH in the addition zone may increase to the point were carbonate alkalinity combines with also the higher localized calcium to create calcium carbonate precipitation thus removing that calcium and alkalinity out of the addition. In other words the resulting addition will be less than expected due to the amount used in precipitating. If there are pumps or heaters in the addition zone you will also increase incrustations on impellers and the heating element.
When the addition is slow as not to impact PH or if using recipe 2 there is a good chance that this effect will not happen.

[apexi]

<a href=showthread.php?s=&postid=13131775#post13131775 target=_blank>Originally posted</a> by jdieck
Usually if using the recipe 1 which increases PH, the PH in the addition zone may increase to the point were carbonate alkalinity combines with also the higher localized calcium to create calcium carbonate precipitation thus removing that calcium and alkalinity out of the addition. In other words the resulting addition will be less than expected due to the amount used in precipitating. If there are pumps or heaters in the addition zone you will also increase incrustations on impellers and the heating element.
When the addition is slow as not to impact PH or if using recipe 2 there is a good chance that this effect will not happen.

Thanks, this makes perfect sense. Drip dosing with a peristaltic pump then would be slow enough as to never cause any precipitation due to a dramatic increase in PH in the addition area. Before when I was doing it manually, and I dumped in the Alkalinity, you could see the "white clouds" that formed in the water immediately upon pouring it into the sump, caused by the dramatic PH change in the local area of addition. In a sump with decent flow, the effect is very short lived as the solution disperses and gets sucked up the return line. Now that I'm dripping with the dosing pumps, you never see any color changes as the drops are too small to cause any significant PH changes.