Auto-Water Change questions

[Stevorino]

Finally got my Auto-Water Change system using an Apex DOS setup last weekend - so far it's been working out exactly as planned. A week in, I've had a few questions come up and would love to hear experiences from other AWC'ers...

1) How much do you auto-change per week/month? I have a 140g total system and changed 30 gallons this week... or 20%. That would have me set to do 80% a month, which seems a little high based on what I've been reading elsewhere... I'd love to hear results that people have had when they tried different amounts.

FWIW - My personal philosophy on this AWC system is to spend a little bit more cash on salt/water for these frequent water changes to decrease the amount of time I have to spend on on weekends manually cleaning the tank.

2) I mix my salt in the same container that the AWC draws from. This morning I realized that unless I pause the DOS manually, there will likely be a few auto-draws from the container within a couple hours after the mixing.... is it really going to impact fish/corals that much to have some very recently mixed water pushed into the system? We're talking about less than a liter into a 140g system... I'm aware that recently mixed water is not good for the livestock... so this is more of a question of how much of an impact it really has when it is such a small part of the overall volume.

3) Now that the AWC system is up... I'm trying to decide how frequently I need to do a full out siphon/bucket water change like I used to do... I'd love to hear results/experiences from others on a good frequency. Obviously, I made this investment to cut down on that... so I'm hoping to do it less frequently...

4) I also have a nano and am considering plugging that into the system as well. The thought would be to do a 100% water change a month (30g overall system). It does NOT currently have a skimmer... so the hope is that this would help the nano stay super healthy. Anyone try this before? Would love to hear experiences/results!

 

[Mebeknob]

I don't run a AWC system, but I will soon!
1)Because you are changing a little daily, it won't be a full 80%. So keep that in mind. I can do the math if you like to find the exact percentage

 

[p7willm]

I have been doing AWC for only 1 month but

1) I change 7.7 gallons on a 75 gallon display with 20 gallon sump and my water parameters are pretty good, except calcium is a low so I am increasing kalk in the ATO

2) I do my changes over 1 hour using a profile cause with the wizard you can not tell programmatically when it is running and I mix right after an addition so the water has over 20 hours to settle. I did turn off water change when I used the wizard and did constant changes.

3) Like I say it has only been a month and all my numbers are fine. If that continues, and the tank continues fine, I have no plans to use the bucket ever again.

4) I moved everything, one fish, from my nano to the bigger tank cause I was spending more time taking care of the nano and it was not doing as well as the big tank.

 

[Stevorino]

I don't run a AWC system, but I will soon!
1)Because you are changing a little daily, it won't be a full 80%. So keep that in mind. I can do the math if you like to find the exact percentage

True - Based on Randy's article, I've assumed that my 80 gallon/week really equates to about 69 gallon/week - which is right at 50% Tank volume... that's a lot per month...

 

[Stevorino]

I have been doing AWC for only 1 month but

1) I change 7.7 gallons on a 75 gallon display with 20 gallon sump and my water parameters are pretty good, except calcium is a low so I am increasing kalk in the ATO

2) I do my changes over 1 hour using a profile cause with the wizard you can not tell programmatically when it is running and I mix right after an addition so the water has over 20 hours to settle. I did turn off water change when I used the wizard and did constant changes.

3) Like I say it has only been a month and all my numbers are fine. If that continues, and the tank continues fine, I have no plans to use the bucket ever again.

4) I moved everything, one fish, from my nano to the bigger tank cause I was spending more time taking care of the nano and it was not doing as well as the big tank.

dang it, I really should have tested my water beforehand... I guess I should go do it really quick this afternoon... so I can actually see the results for myself.

On the Nano - I'm just about where you are on it as well... I just feel like it's all this work to keep it up and has never taken off like my big tank. I'd love to see if a continuous water change system on that where you were constantly turning it over would be a big help or not...

 

[p7willm]

The other thing I thought about, other than shutting it down, was tying the 2 tanks together with a common sump. But, the plumbing seemed to be a lot of work unless the tanks were right next to each other and that would have looked silly.

 

[cb684]

Have you seen this:
https://www.hamzasreef.com/Contents/Calculators/EffectiveWaterChange.php
I usually stop the AWC during the time I am mixing the salt. In my case this occurs every 3 or 4 weeks. The amount of water change during those 4 or so hours is so small that does not change the overall water change of my systems.
I do 1% / day. What is about 7-8% / week. I believe this amount is enough to replenish micro elements in my system (that is the reason I run AWC). If you are using AWC to keep NO3 and PO4 low, you might need more than that. So, in other words, the amount of water changes depends on what you are trying to achieve...
Good luck.