Alkalinity and water changes

[WildReefGuy]

ever since I had to downsize my tank to a 25 g I’ve had much lower Alk levels around 7.7. I do a 25% weekly water change to keep parameters in check with it being a smaller system. I use instant ocean reef crystals. When I do a water change will it raise my Alk or should I be dosing with like Brightwell’s alkalin 8.3?

 

[MnFish1]

First I would verify the number with at least a couple tests. (different tests). The Brightwell - I believe contains borate - as compared to carbonate. I would not use it for a couple reasons - which I'm not going to go into.

Are you growing corals? or fish only. an Alkalinity of 7.7 is actually fine. What is your pH

 

[WildReefGuy]

First I would verify the number with at least a couple tests. (different tests). The Brightwell - I believe contains borate - as compared to carbonate. I would not use it for a couple reasons - which I'm not going to go into.

Are you growing corals? or fish only. an Alkalinity of 7.7 is actually fine. What is your pH

Ph was 8.0- 8.15 and yes I have a few softies and some sps. 1 clown, 1 sixline wrasse, 1 blenny

 

[WildReefGuy]

Ph was 8.0- 8.15 and yes I have a few softies and some sps. 1 clown, 1 sixline wrasse, 1 blenny

I just heard 9 Dkh was better to be at and promoted coral growth

 

[mdb_talon]

ever since I had to downsize my tank to a 25 g I’ve had much lower Alk levels around 7.7. I do a 25% weekly water change to keep parameters in check with it being a smaller system. I use instant ocean reef crystals. When I do a water change will it raise my Alk or should I be dosing with like Brightwell’s alkalin 8.3?

Reef crystals is a high alk salt so yes it will increase your alk levels when you do a WC. How much obviously depends on how big a change. If we assume IORC is around 12 dkh and you do a 20% water change then your alk would go to around 8.5dkh for example.

 

[WildReefGuy]

Reef crystals is a high alk salt so yes it will increase your alk levels when you do a WC. How much obviously depends on how big a change. If we assume IORC is around 12 dkh and you do a 20% water change then your alk would go to around 8.5dkh for example.

So should I keep doing weekly water changes to keep it at a consistent 8 ish? Or bi- weekly? I change 20 to 25%.

 

[MnFish1]

Ph was 8.0- 8.15 and yes I have a few softies and some sps. 1 clown, 1 sixline wrasse, 1 blenny

I would not be concerned about an alkalinity of 7.7

 

[mdb_talon]

doing weekly water changes to keep it at a consistent 8 ish? Or bi- weekly? I chan

I would say so yes. If it is at 7.7 now that's not a bad thing. However if it is at 7.7 and you have consistently been doing water changes with a high alk salt then presumably if you stop the water changes you are going to see a drop. In any case it seems what you are doing now is keeping your dkh just fine so would not stop it. If you want it a little higher then ya I would just do a little bigger or more frequent water changes. Eventually you may get to a point that dosing makes more sense(effort and $$) than water changes. Water changes are generally an expensive way to keep your alk up, but they do serve other purposes than just alk as well so if you are doing them anyway keep using the high alk salt and you should be fine until your consumption of alk/calc go up more.

 

[dwest]

I did 25% water changes (monthly) with reef crystals while maintaining alkalinity of 8 dKH (before the WC) for many many years. I had no problems whatsoever. It was one of my most successful periods as a hobbyist. The kicker was I had fish, softies, and LPS.

Now that I have mostly acros, I make sure to do smaller, more frequent changes to keep alkalinity more stable.

I guess my point is that it matters what you keeping.

 

[WildReefGuy]

I would say so yes. If it is at 7.7 now that's not a bad thing. However if it is at 7.7 and you have consistently been doing water changes with a high alk salt then presumably if you stop the water changes you are going to see a drop. In any case it seems what you are doing now is keeping your dkh just fine so would not stop it. If you want it a little higher then ya I would just do a little bigger or more frequent water changes. Eventually you may get to a point that dosing makes more sense(effort and $$) than water changes. Water changes are generally an expensive way to keep your alk up, but they do serve other purposes than just alk as well so if you are doing them anyway keep using the high alk salt and you should be fine until your consumption of alk/calc go up more.

That’s what I was thinking I would like to save more money if I can cut my water changes in half but don’t want to start dosing and mess my whole system up. I have Brightwell’s alkalin 8.3 but don’t know if I should be using something with it or using a completely different approach to dosing

 

[MnFish1]

That’s what I was thinking I would like to save more money if I can cut my water changes in half but don’t want to start dosing and mess my whole system up. I have Brightwell’s alkalin 8.3 but don’t know if I should be using something with it or using a completely different approach to dosing

I would suggest - you might be overthinking. Stop focusing on tests - and start focusing on the animals in your tank. My guess (and it is a guess) - is that if your alkalinity was 8 - there would be no question . An alkalinity of 7.7 is not going to cause problems if it drops - you may need supplements. I do not think you need to worry - and PS - you can also add kalwasser - daily - as needed to increase alkalinity

 

[MnFish1]

I would say so yes. If it is at 7.7 now that's not a bad thing. However if it is at 7.7 and you have consistently been doing water changes with a high alk salt then presumably if you stop the water changes you are going to see a drop. In any case it seems what you are doing now is keeping your dkh just fine so would not stop it. If you want it a little higher then ya I would just do a little bigger or more frequent water changes. Eventually you may get to a point that dosing makes more sense(effort and $$) than water changes. Water changes are generally an expensive way to keep your alk up, but they do serve other purposes than just alk as well so if you are doing them anyway keep using the high alk salt and you should be fine until your consumption of alk/calc go up more.

Im curious - not arguing - given the margin of error - is 7.7 really that much different than 8?

 

[mdb_talon]

Im curious - not arguing - given the margin of error - is 7.7 really that much different than 8?

I'm not sure why you think I am suggesting there is a significant difference? As I stated in what you quoted... 7.7 is fine. My point(and a valid one in my opinion) is that if it is 7.7 with consistent WC using a high alk salt then it will likely drop without the WC so he should keep doing what he is already doing. Also mentioned if he wants it higher he could do a bit larger or more frequent changes.

Precision of test or the MOE does not change that point(ie whether the true number is 7.7 or 8.3 a larger water change using IORC is going to increase it a bit). Again thought I am not suggesting whether he should want it higher or not. I run around 9 myself (give or take .5 either way depending how much my coral decide to grow that day), but some people do fantastic at 7 and whether one is better than the other is not an argument I'm making which is why I said 7.7 was not a bad thing.

 

[MnFish1]

I'm not sure why you think I am suggesting there is a significant difference? As I stated in what you quoted... 7.7 is fine. My point(and a valid one in my opinion) is that if it is 7.7 with consistent WC using a high alk salt then it will likely drop without the WC so he should keep doing what he is already doing. Also mentioned if he wants it higher he could do a bit larger or more frequent changes.

Precision of test or the MOE does not change that point(ie whether the true number is 7.7 or 8.3 a larger water change using IORC is going to increase it a bit). Again thought I am not suggesting whether he should want it higher or not. I run around 9 myself (give or take .5 either way depending how much my coral decide to grow that day), but some people do fantastic at 7 and whether one is better than the other is not an argument I'm making which is why I said 7.7 was not a bad thing.

Sorry if I wasn't clear - or didn't respond to the right post - I was not suggesting anything about your post