How stable does stable have to be to be stable?

[glb]

I have a 12g nano with softies and lps and I'm wondering what exactly 'stable' means when people talk about keeping their tanks healthy. I'm buying better test kits now so I'm becoming more vigilant and may do testing daily for a week to see how much my tank changes. I'll post the results and look forward to feedback on any fluctuations I might have. More to follow...

 

[pickupman66]

to me, stable is the tank conditions not fluctuating on a weekly/monthly basis. for each param it may be slightly different.

a Stable PH does not change more than .1 in an hour and .2 daily. It will Fluctuate.
a Stable Alkalinity stays within .05 Dkh on a weekly basis - Shoot for it to remain the same when tested from week to week, month to month.
stable salinity does not change more than 1 or two ppt within a few hours. no more than 3ppt jump in a day.
stable ammonia and nitrites are NEVER present
Stable nitrates are below 15 I guess. not constantly spiking
stable temp is less than 1° change within an hour. Most tanks should be stable to within a degree for days on end.

 

[Russellaqua]

I agree with pickupman66 above. I'd like to see the salinity change less than 3 ppt per day. Stability means just that. Things aren't changing in either the short or long term. The pH will fluctuate a bit during the day, but this is a normal cycle that nothing can, or should, be done about. When measuring your pH it's best to do it at the same time of day. Otherwise you're measuring it at different points in the cycle and the numbers are hard to compare to each other to get an idea of how things are going.

 

[jservedio]

Alkalinity changes of less than 0.05dkh in a day is flat out impossible in an SPS system unless you are constantly infusing Alk at EXACTLY the rate is is being used - and even the most sensitive hobbyist test devices can't measure this. A Hanna Checker (what I use) can only get within 0.056dkh - that's 1ppm. Unless you have a several thousand dollar lab-grade spectrometer, you can't measure alkalinity changes beyond 1ppm (0.056dkh).

Stable Alkalinity for me is a fluctuation of 2-3ppm in a day during testing or less (0.17dkh) and less than 8-10ppm over the course of a week (0.5dkh). This means that if you test at the exact same time every day, you will only be off 2 or 3 ppm. If you test at a different time of the day, your numbers can be wildly different, yet still be "stable" because of the way dosing works (if you Dose 2-part or use Kalk and not a Calcium Reactor).

Lets say you have an SPS system that uses 1.5dkh/day of Alkalinity and you have a dosing system that doses 6 times a day. That still means you are going to have a fluctuation of 0.25dkh between doses that are only 4 hours apart. Of course you can raise the number of doses to bring this down, but the more times you dose in a day, the lower each dose will be. And the lower the dose, the less accurate the doser is.

For example, if I test my tank at 1:05pm (right after my doser goes off), I may have an alkalinity of 10.36dkh, but if I test again at 5:00 (5 minutes before the doser goes off again), I may be down to 10.19dkh. However, just waiting 5 more minutes, I will test at exactly 10.36dkh again. This fluctuation throughout the day doesn't mean that your system is not stable though.

 

[glb]

Great info! Thanks everyone!!

 

[beaslbob]

I have a 12g nano with softies and lps and I'm wondering what exactly 'stable' means when people talk about keeping their tanks healthy. I'm buying better test kits now so I'm becoming more vigilant and may do testing daily for a week to see how much my tank changes. I'll post the results and look forward to feedback on any fluctuations I might have. More to follow...

How stable does stable have to be to be stable?

any positive stability is defined as stable. The more positive the more stable though.


FWIW (and a personal pet peeve) stable and constant are actually different. For instance, it is entirely possible to have change values that are very stable. Example- daily pH fluxuations. If something changed the system and the system tends to return to that original state it is stable. Even if the original state fluxuates.

And it is quite possible to have constant valuse which are very unstable. For instance, say ammonia. It can be zero for long times then a fish dies and ammonia increases killing more fish and so on. So constant but unstable.

My pet peeve is that I strive for a stable environment which is healthy for the critters. Not a constant unstable environment which at the moment may be healthy.


my .02

 

[glb]

Ok, here's the beginning of my stability experiment. On 9/18, I started using my salifert test and got no3 readings of 25! Alk was 146ppm, down from 172 on 9/7. I did a 2 gallon water change.

9/20. 2 gallon water change. Test results after:

No3: 10
ph: 7.9
Alk: 135 ppm
Mg: 1140
Salinity: 1.0255
Ca: 450

I added 20ml of Brightwell labs mg, which should bring up the mg 52ppm, which would be 1192. I had no idea you had to add so much! I'll keep adding that amount daily until I reach c. 1300. I'll also see how much is depleted daily.

My alk is dropping but still within normal range. Maybe mg going up will help.

Calcium never changes. It's always between 400-450 and I never have to supplement.

I'm going to test daily for a week. More results to follow and suggestions are welcome!!

 

[glb]

any positive stability is defined as stable. The more positive the more stable though.


FWIW (and a personal pet peeve) stable and constant are actually different. For instance, it is entirely possible to have change values that are very stable. Example- daily pH fluxuations. If something changed the system and the system tends to return to that original state it is stable. Even if the original state fluxuates.

And it is quite possible to have constant valuse which are very unstable. For instance, say ammonia. It can be zero for long times then a fish dies and ammonia increases killing more fish and so on. So constant but unstable.

My pet peeve is that I strive for a stable environment which is healthy for the critters. Not a constant unstable environment which at the moment may be healthy.


my .02

I agree. I'm just trying to really understand these concepts so everyone's comments really help!

 

[Zero Nitrates]

Good topic. I think it relative to size of the tank, livestock and additives that are used.
I want to see how this varies from tank to tank and person to person. Hope to see more comments.
My dkh drops 3 every day and swings back up 3 everyday when I dose. Sounds bad but it is working with my tank.

 

[glb]

Good topic. I think it relative to size of the tank, livestock and additives that are used.
I want to see how this varies from tank to tank and person to person. Hope to see more comments.
My dkh drops 3 every day and swings back up 3 everyday when I dose. Sounds bad but it is working with my tank.

I'm going to take my readings in a few hours like I did yesterday and I'll post the new ones and how much they differed. This should be very interesting!

 

[glb]

Ok. Here's the results for day 2

NO3: 10ppm (no change)
Alk: 139ppm (+4)
Mg: 1200ppm (+60)
Ca: 400ppm (-50)
Ph: 7.8 (no change)
SG: 1.025 (-.05)
Temp: 78F (no change)

The projected mg level after dosing 20ml of Brightwell mg was 1192, so the dosing was right on. After these readings, I dosed 20ml more mg, so tomorrow's readings should be 1250 more or less. Tomorrow I'll also do a 2g water change as I'm trying to bring the nitrates down to 5 by changing 2g every other day. After it's there, I'll probably change 1g twice a week to maintain. I'm wondering if the lower ca is related to the higher mg. My stability experiment goes on!

 

[glb]

Here's the tank today:

 

[Zero Nitrates]

Do you think a water change will bring your alk down?

 

[glb]

Oh the alk is fine. It's in ppm. That's probably c. 8.5kh. I just got a Hanna checker and that's how it measures.

 

[glb]

No actually it's low. The alk is 7.8kh.

 

[glb]

Here's day 3

NO3: 10 (same)
Alk: 134ppm (-5ppm)
Mg: 1400ppm (+200ppm)
Ca: 475ppm (+75)
Ph: 7.8 (same)
Temp: 78 (same)
SG: 1.026

I did a 2g water change this morning to continue to lower nitrates. These tests were done about 5 hours later. The alk is continuing to go down so I'll need to add something. The Seachem buffer I have is also supposed to raise ph and has mg and ca in it, which I don't need. The ca going up could be in part the water change, but could it be that more's in the water column because the mg is up? As far as the mg reading, I have no idea, but I don't think it's right. I'm going to clean the vial thoroughly and test again tomorrow. Probably a testing error on my part. I'm thinking soda ash to raise alk. Any suggestions or constructive criticism would be greatly appreciated!

 

[beaslbob]

Here's the tank today:

that's all that matters.

Looks great

 

[glb]

that's all that matters.

Looks great

Thanks! I wish my zoas weren't disappearing though! Guess I'll have to buy more ricordea and acans!

 

[glb]

Well, I'm way too tired to test today so I'll report in tomorrow. I'll add phosphate, as my hanna checker came in the mail today!

 

[pickupman66]

Funny.. I only test now when something looks amis. I did discovering have a certain coral that burns tips when phosphate goes up. Usually my pellets are low.

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