Normal pH + high dK

[ShrimpBandit]

Indeed you are! Over time as you do continuous water changes you will dilute the water more and more making any contaminants less dangerous over time. I would get a dual line TDS meter, they are 20 bucks on amazon and are important so you know when your filters need to be changed (namely the DI resin). A lot of people use this one https://tinyurl.com/y2kjnx5b (Just be sure to read the instructions to get accurate readings)

Once your TDS reaches 2 or more, means your DI resin likely needs to be changed. Could also be the membrane or carbon/sediment filter but those last abit longer than DI. You can also get a pressure gauge but thats not super important if you are happy with your current water output. Its mostly to make sure your filter is running at max efficiency and I also think It may be able to tell you when you need to change your membranes (my logic is that if PSI goes higher than normal, then the membranes are maxed out).

My BRS kit included both of those things, so it sounds like a I chose well! Thanks!

 

[ShrimpBandit]

To circle back - I bought the 6 Stage Deluxe RODI unit from BRS and installed it about 3 months ago. I added a second brute to my setup and now I have a freshwater bin and a saltwater bin.

I check the tank parameters just before and 24 hours after weekly 10-20% water changes. Here's where we are 3 months later:

TANK:
dKH has been 13/14 for about a month
pH over the last 3 months 8-8.2

RODI FRESH WATER:
dKH - 0

RODI SALTWATER @ 63°/1.020:
dKH - 10

I mix the water for weekly changes light because I'm still trying to bring the tank salinity (1.027) and dKH (13/14) down to more ideal parameters.

However, if just the diluted salt mix gets me to 10 dKH, perhaps I ought to seek out another option? Currently using Instant Ocean. *shrug*

 

[Garf]

Have you calibrated your refractometer? I suggest using @Randy Holmes-Farley DIY solution.

 

[ShrimpBandit]

Have you calibrated your refractometer? I suggest using @Randy Holmes-Farley DIY solution.

I did, but how would that affect the dKH reading?

 

[Garf]

I did, but how would that affect the dKH reading?

The higher the salinity, the higher the DKH. Folks have trouble with off the shelf calibration solutions and calibrating with fresh water is inaccurate. Now you’ve got some RODI, and assume you’ve got a bit of table salt, make a calibration standard to prevent salinity errors.

 

[ShrimpBandit]

The higher the salinity, the higher the DKH. Folks have trouble with off the shelf calibration solutions and calibrating with fresh water is inaccurate. Now you’ve got some RODI, and assume you’ve got a bit of table salt, make a calibration standard to prevent salinity errors.

This hobby comes with so much homework. Guess I'll check my work in the morning.

FWIW, I'm checking my salinity with a calibrated (manufacturer directions) refractometer and a hydrometer, and the dKH with just an ATI test kit. I've definitely seen progress in the tank since switching to RODI water. However, I tested the salinity of the fresh and salt bins at the same time, same temp, side by side. The only variable was the salt mix. I'm not even using enough to get to 1.025 in the bin, and I'm already at 10 dKH. Is there a mix that's lower at the start?

 

[Aqua Man]

API Alk test says my tank is at 8.0 DKH
Salifert Alk test says 9.6

manufacturer of my refractometer says calibrate with RoDi water.
bought some calibration fluid and made some like advised. My refractometer was off. 1.028 I thought it was 1.025

 

[ScottB]

This hobby comes with so much homework. Guess I'll check my work in the morning.

FWIW, I'm checking my salinity with a calibrated (manufacturer directions) refractometer and a hydrometer, and the dKH with just an ATI test kit. I've definitely seen progress in the tank since switching to RODI water. However, I tested the salinity of the fresh and salt bins at the same time, same temp, side by side. The only variable was the salt mix. I'm not even using enough to get to 1.025 in the bin, and I'm already at 10 dKH. Is there a mix that's lower at the start?

Yes. Red Sea blue bucket mixes to 8. I believe the Tropic Marin does as well.