Questions about raising kh- advice please

[happychem]

For their tank???

Yes, because as you've seen it's very easy to increase KH or pH to be more stable or to match wild conditions for breeding or wild caught fish. Conversely, it is both difficult and expensive to remove the buffer and lower TDS.

You needn't worry about pH swings at water change. The activity of crushed coral is slow and the difference in KH before and after water changes will not be serious.

If you wish to err on the side of caution, two 30% water changes are almost equivalent to a single 50% water change, so you can do two 30% changes - so a smaller percent change in TDS - spread through the week and get the same level of water quality as you would with a single 50% change.

 

[hike13]

Yes, because as you've seen it's very easy to increase KH or pH to be more stable or to match wild conditions for breeding or wild caught fish. Conversely, it is both difficult and expensive to remove the buffer and lower TDS.

You needn't worry about pH swings at water change. The activity of crushed coral is slow and the difference in KH before and after water changes will not be serious.

If you wish to err on the side of caution, two 30% water changes are almost equivalent to a single 50% water change, so you can do two 30% changes - so a smaller percent change in TDS - spread through the week and get the same level of water quality as you would with a single 50% change.

I'm a novice here so I'm not sure what you mean by TDS.

Hypothecically (sp) let's say I put the crushed coral in my filter and get my kh up about 3 dKH and my ph is stable. I do a 30-40% change with my tap water. The remaining water in the tank should have enough buffer to compensate until the new water runs through the crushed coral, correct.

I just want to clarify before I anger my fish.

Thanks for the help everybody. This site has been a wealth of info for me.

 

[ashdavid]

"TDS" Total dissolved solids. These play a big part in the health of your fish, too much of a big change can adversly affect them.

It is not really a question of the remaining water having enough buffers in it, more so I am concerned with changing the waters chemistry too much too quickly. Imo it is best to get the change waters chemistry as close to the tanks as possible before doing a water change(within reason that is)

The amount of coral you put in the change water can be anything from a handfull to a few handfuls, as Happychem stated earlier coral raises the kh slowly ,plus it will only raise the kh to a certain point, so any coral in excess is of no concern. So if you have no time to do several times a week water changes, you can put the coral in your change water and have a little piece of mind.

 

[happychem]

The point of the crushed coral in this case is less to raise the KH to a target level, and more to act as a compensator.

After your initial addition the tank chemistry will start to change and will continue to be somewhat unstable for the first few weeks. If you're doing 50% - or equivalent - water changes weekly, it will take about 8 weeks for your water chemistry to return to equilibrium, assuming that the dissolution rate of the crushed coral remains more or less constant. At this point your tank chemistry - KH in this case - will slowly increase through the week to the same value as the week before, the water change will bring it back to the previous level, then it will creep up again, thus your tank KH, and pH is stable. This is as stable as it can get without pouring in the crushed coral and bringing your pH up to about 9.

If you supplement the KH/pH of your change water, then you're not removing the extra carbonates that have built up over the course of the week, so KH (and pH as a concequence) will continue to increase each week, which in the end is not "stable".

 

[happychem]

I should add. Just because your water pH and KH is at low as it is does not mean that you must buffer it. Changing your maintenance routine to 2 30% changes per week will probably be sufficient to keep your tank's buffer at a safe level. The only catch is that you can't skip a week, but that is the drawback of very soft water.

 

[hike13]

I should add. Just because your water pH and KH is at low as it is does not mean that you must buffer it. Changing your maintenance routine to 2 30% changes per week will probably be sufficient to keep your tank's buffer at a safe level. The only catch is that you can't skip a week, but that is the drawback of very soft water.

I guess what it comes down to for me is what would be safer and healthier for my fish. Dealing with the crushed coral or just changing my routine as you suggested happychem? I definitely don't want too stress anybody out (including me).

 

[happychem]

Both should be equally effective. IMO, smaller, more frequent water changes (with the same total equvalent % change) are better than single large ones. However, the single larger one is definitely more convenient and easier to work into the schedule.

Personally, I'd go with a bit of crushed coral. That way if you have an improptu vacation, or you can't do a water change for a couple weeks - because sometimes it happens - then you know that at least your pH won't crash.

 

[ashdavid]

TAfter your initial addition the tank chemistry will start to change and will continue to be somewhat unstable for the first few weeks. If you're doing 50% - or equivalent - water changes weekly, it will take about 8 weeks for your water chemistry to return to equilibrium, assuming that the dissolution rate of the crushed coral remains more or less constant. At this point your tank chemistry - KH in this case - will slowly increase through the week to the same value as the week before, the water change will bring it back to the previous level, then it will creep up again, thus your tank KH, and pH is stable. This is as stable as it can get without pouring in the crushed coral and bringing your pH up to about 9.

If you supplement the KH/pH of your change water, then you're not removing the extra carbonates that have built up over the course of the week, so KH (and pH as a concequence) will continue to increase each week, which in the end is not "stable".

But, this provides a bit of a yo-yo effect , the changes in the tanks chemistry are very small if water changes are done regularly which is true will keep the ph stable. However if left for too long without a water change the KH difference in the the change water and tank water can become quite big and when a big water change is performed the change in the water chemistry can become quite big.

Ime crushed coral will only bring your PH up to a certain point, usually about 8-8.2 PH, so once you get to this point the ph becomes stable. As with raising the KH in the change water, if crushed coral is used the KH will not exceed the tanks KH,( it is more likely to be less due to the time taken for crushed coral to take effect) And IMO will give a much more stable PH/KH due to the fact that you are keeping the waters chemistry relatively similar.

I would leave the PH alone, and do regular 30-40% bi-weekly water changes to compensate for the buffers being used in the nitrification process. But I am biased towards soft water fish.

 

[ashdavid]

The point of the crushed coral in this case is less to raise the KH to a target level, and more to act as a compensator.

I just reread your post and realised what you were trying to say. This is very true Happychem, but Ime it is easier to get the PH to a point and keep it there, especially with crushed coral. I suppose with anything there are more than one way to skin a cat.

Anyway, hike13 all of these methods are sound advise , but remember one thing- regular water changes are vital to keeping the tanks water stable.

 

[hike13]

ash and happychem, thanks for the info. I'm going to try a small amount of crushed coral and see how that goes. I put a tablespoon in the filter this mornig so I'll see if I get a noticeable kh change over the next week. As much as I would like to do smaller more frequent water changes there is no way I can make it work with time constraints due to work and kids. My wife already gives me the stank-eye when I go through my cleaning/change routine.

I do have one more question about the change water. If I end up storing change water and put coral in it to try to keep in line with the tank do I just throw it in the bucket or do I need to agitate the water in order for the coral to dissolve.