stable dkh - am i going crazy????

[saltyair]

A little history first: been carbon dosing for 8 months @ 20 ml vinegar per day - in a 220 volume of water. 180 dt. Was at 45 ml vinegar per day 2 months ago. Major changes over the last three months 3 new hydra LED went down to 10 gal per week WC (from 15 gal per week) switched from DD salt to aquavitro salt.

My NO3 and PO4 are nil (fairly stable no major swings)
Cal 420 (420 - 450 swings)
mag 1380 (elos) very stable
PH - 8.0 to 8.1

dose kent turbo cal in top up (once a month I add 5mls mag)
dose kent superbuffer manual
My big issue over the last 3 months have seen swings of 7-10 dkh some times on a bi-weekly basis. I always seem to be chasing 9dkh.

Over the last week I have been checking my alk daily - here is the diary.

April 19th Added 10 mls alk morning - tested @ 5pm - 169ppm
April 20th 10gal WC - tested @ 4pm - 175ppm
April 21st 5mil alk in AM - tested @ 4pm 170ppm
April 22nd 0 mils added AM - tested @ 5pm 164ppm Added 10mls PM (after results)
April 23rd 0mils added AM - tested @ 8:30am 172ppm

Would like to hear some feed back. I do realize I should test at the same time everyday (this morning was an exception - will test again tonight)

So is this considered stable? Also is this a high uptake of alk. Most of my sps are still under 3 inches. I don't have a clam. I do have a fair amount of coralline algae.

Other stuff - carbon and rowa in carbon reactor
Over size skimmer
Sock every other week
refugium (20 gal)

I have experienced some bleaching and browning i believe a combo effect of adding new hydras and alk swings. Lost a milli and green dragon frag.

 

[mos90]

you dont seem to be consistent with your dosing but those #'s seem stable enough. i would recommend dosing the same amount each day either manually or with a dosing pump. on my tank 300g, i dose 75ml fo brs alk every day with a doser. spread out to dose every hour.

you should definitely test the same time in the day. my tank will vary 1 dkh from morning to evening.

i had the same issue when i switched to leds. lost a few colonies but everything bounced back after i figured out the sweet spot.

i would say you have a very low alk uptake.

 

[michaellee64]

You want to be real careful having your Dkh over 8 while carbon dosing due to some corals being sensitive to it. The most susceptible seem to be montiporas. I lost several large encrusting montiporas to this when I used to dose vinegar. I also had several acropora colonys brown out, but regained their color when I quit carbon dosing.

 

[saltyair]

I agree that my dosing is up and down right now - but the reason is I looking for the right amount per day to dose. right now it seems like 10mls a day seems right?
over the next few weeks I will be testing 2x a week just to be sure.

good to hear that i have low alk uptake - Iwas thinking 10ml of kent was a lot.

you dont seem to be consistent with your dosing but those #'s seem stable enough. i would recommend dosing the same amount each day either manually or with a dosing pump. on my tank 300g, i dose 75ml fo brs alk every day with a doser. spread out to dose every hour.

you should definitely test the same time in the day. my tank will vary 1 dkh from morning to evening.

i had the same issue when i switched to leds. lost a few colonies but everything bounced back after i figured out the sweet spot.

i would say you have a very low alk uptake.

 

[mos90]

try to find the amount of daily dosing to keep alk around 8. keep it steady and alk wont fluctuate much. keep waterchange alk about the same as the tank if possible.

 

[HighlandReefer]

How are you adding the kent superbuffer to your tank?

If you add all the kent superbuffer at one time, this could result in calcium carbonate precipitating out, which the part that precipitates out does nothing to increase your alk level. It should be added slowly, dripping is best.

Using baking soda doesn't increase the pH locally where it's added, so you're less likely to get calcium carbonate precipitating out when adding it all at once.

Your alk measurements ranged between 169 - 175 ppm or 9.5 - 9.8 dKH. The error of margin for most alk test kits is about 0.2 dKH or more if you're not careful determining the end point of the titration. That's not much swing.

 

[saltyair]

Thanks for the advice. I will be dropping the dkh to 8 just to be safe.
Unfortunately right now I have to manually dose since I don't have a dosing pump and I have cal in my top up.
If I were to put alk in my top up how would I measure the proper amount (10ml) per day since it's variable and the concentration will also be variable.
Appreciate the help

 

[mos90]

Do you top off manually daily?

if you do not top off manually i wouldnt go that route. dosing will be inconsistent. i would just dissolve 10ml per day to start in some ro/di water test daily before dosing and adjust accordingly

 

[bertoni]

Those numbers seem fine to me, and very stable. The coralline can consume a lot of calcium and alkalinity, so I wouldn't worry much. Your system seems normal to me.