Can't get dKH up .....

So I've been trying to raise my dkh for a while. I have used the dry Seachem and now the Brightwell Aquatics Alkalin 8.3, but my dkh will not move from around 6.5 to 7.
Here are the full water parameters as of tonight:
Ammonia: 0
Nitrite: 0
Nitrate: 40 (working on that)
Copper: 0
dKH: 7
Calcium: 400 (raising that a little tonight)
Magnesium: 1500
Phosphate: 0
Specific Gravity: 1.0258
Water Temp: 80.4
pH: 8.00

 

It looks like your pH is a bit low too, I like to keep mine at between 8.2-8.4. I am not sure what brand of salt you are using, but in the long term you may want to use a brand with better buffering capacity like Tropic Marin. You can also use a good quality buffer like Triple-Buffer or something similar to raise your pH and alkalinity in a short period of time.

 

Are you sure on the SG being 1.025? Are you using a refractometer or a hydrometer to get that reading?

I ask because you need your SG around 1.027 to get your Mg up to 1500... are you sure your Mg is at 1500?

While I'm asking those questions, are you sure your dKH is only 7?

Looking over your readings... I get the feeling your tests aren't accurate... have you cross checked your readings w/the LFS?

 

+1

Your PH is fine. I think it's your test kit. Try another one. PH, dkh, and calcium go hand in hand.

 

pH reading was taken last night 3 hours after lights off, during the day it peaks around 8.27 (currently at 8.19) I use a (frequently calibrated) pinpoint pH monitor.

As for the sg, I also use the pinpoint monitor, that I calibrate at 53.0ms about once every 7-8 tests (so far it's been staying very close to 53.0 with the furthest being 53.8 before recalibration)

Also, I use Natural Sea Water from the LFS
I tested the Magnesium 3 times, I got 1500, 1480 and 1500 Red Sea Test
I had to raise the Mag to around 1600-1620 a few weeks ago to get rid of bryopsis (worked great) and my dKH used to be around 8-8.5 but now it's about 7 (API test)

Last month I had the LFS test my params to make sure my tests were accurate, here are the results (left is my result right is theirs):

Calcium: 440/440
pH: 8.17 (pinpoint)/8.2 (test)/8.3(LFS)
Nitrite: 0/0
Ammonia: 0/0
Phosphate: 0/0
Copper: 0/0
sg: 1.0245 (pinpoint)/1.024 (floating hydrometer)/1.024 (refractometer calibrated with 0)/1.027 (LFS with swing arm)1.025 (LFS refractometer)
Mag: 1420/1450
They didn't have a nitrate test so didn't test that

 

Try the little blue pill? Okay I just had to make a joke because when I read the title that was the first thing I thought of was the TV commercial. :

 

I would seriously try another dkh test kit.. did you have the LFS test the dkh.. I didn't see that on you post?

 

Hi Beetle, salinity is not the issue. Try Reef Builder by Seachem(is that the dry you tried?). I have to use two teaspoons daily to keep my Alk up since my tank sucks it up. My SG is .025 and Mag is 1500 ppm.

 

I use kent ph/dkh super buffer.. its raises PH and dHK.. I would do a small water change and use some of that with your saltmix..

 

Are you dosing anything? I started dosing Brightwell's Kalk+2 and it is keeping both Alk and Calc high - my Alk is actually a little too high for my taste.

Also, I've been hearing a little lately about people keeping very successful reef tanks with Alk at the lower end of the normally acceptable scale.

Lastly, I think salt brand is key. I use Tropic Marin and love it. My LFS used to use it, but is now pushing Brightwell's new salt as superior.