alk dosing vs ph

[dutch27]

My alk was consistently dropping below 7 between my weekly water changes, so I started dosing b-ionic to bring it up. I've gotten to a point where I'm maintaining my alk at 8 dkh. My goal was to maintain 9.

 

To increase it to 9 I need to add 19ml per day (44g total system volume). How much is safe to dose at once without spiking the pH too much? I currently do my small maintenance dose in two stages, half in the morning and half in the evening, but we're only talking about 3ml to maintain.

 

I'm probably going to do a DIY dosing setup as per this thread:

http://www.nano-reef.com/forums/index.php?showtopic=187889

 

Eventually I want to get a reef controller that will be able to run my dosing, until then that DIY build looks pretty solid.

[Weetabix7]

It's much better to add all of the Alk in the morning before lights on.

I do that in 2 stages, add half of it, wait a bit, add the other half.

If you can't do that, do half in the morning, second half just before you go to bed at night.

[lakshwadeep]

+1 to adding in the morning (before the lights turn on), when pH is lowest.

 

7 dKH is okay for a minimum; 9 dKH shouldn't be seen as a perfect value. What are your other water parameters? What are the values of your water change water? What livestock are in your tank? Have you noticed any problems with the "low" alkalinity.

 

A good guide to water chemistry:

Part 1: The Saltwater Itself

Part 2: What Chemicals Must be Supplemented

Part 3: pH

Part 4: What Chemicals May Detrimentally Accumulate

[ulver982]

I wouldn't increase the pH more than 0.20 at one time.

[dutch27]

+1 to adding in the morning (before the lights turn on), when pH is lowest.

 

7 dKH is okay for a minimum; 9 dKH shouldn't be seen as a perfect value. What are your other water parameters? What are the values of your water change water? What livestock are in your tank? Have you noticed any problems with the "low" alkalinity.

 

A good guide to water chemistry:

Part 1: The Saltwater Itself

Part 2: What Chemicals Must be Supplemented

Part 3: pH

Part 4: What Chemicals May Detrimentally Accumulate

 

I'm shooting for 8-9 because 7, dropping as low as 6.4 between WCs was making me uncomfortable as I started keeping SPS. I figure 9 is a nice middle ground that would give me room if my demand jumps because I get lazy with my testing.

 

Other parameters:

Ca: 420 (post-wc), 380 pre-wc, haven't started dosing this yet was focusing on getting alk right first

Mg: Unknown

Nitrates: 5-10ppm

 

WC water is around 8dkh and 420ppm Ca (reef crystals). Until I started dosing maintenance even post-wc I didn't see alk over 7 much. Now it's leveled out to a steady 8, pre and post-wc.

 

I didn't notice any problems with my alk being low, other than blastos dying. But that's some other mystery problem as I can't seem to keep any blastos alive anymore. They're some of my favorite LPS too. I just feel that I should keep a slightly higher than min alk at a consistent level as I keep more and more SPS. As of now I have 5 acros, 2 encrusting montis, and a decent sized orange cap, along with a mini-elegance, acan, dendro, duncan, two hammers and chalice frag eating up alk & ca as well. Also have various zoas and some shrooms.

 

Ulver - I suppose the question is, is there any definitive data out there that shows a swing in alk by x dkh swings pH by 0.2?

 

Weet - the only issue with that, is that I run my fuge light all night until I leave for work in the morning, not sure how much that offsets the normal pH drop. Haven't tested my day vs night pH. For the maintenance dosing I do half at night, half in the morning.

[Amphiprion1]

See the following thread: http://www.nano-reef.com/forums/index.php?showtopic=234414

 

It has the applicable information you are looking for. I'll stress, as I did in that thread, that the end result is variable.