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07/21/2018, 08:31 AM | #1 |
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Question about stability
Something I hear often is “Don’t chase numbers, chase stability”
What is the acceptable change in Alkalinity from day to day to be still considered stable? Sent from my iPhone using Tapatalk |
07/21/2018, 09:05 AM | #2 |
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That’s a VERY hard question to answer accurately. Problem is alkalinity is related to too many other factors. Lower nutrient levels will make alkalinity shifts more sensitive with stony corals. Higher light levels will impact a corals response as well.
We can’t definitively say that a day to day swing of 0.2 will be unnoticed but 0.21 will result in tip burn in acropora tortusa for example. Too much gray area and interrelated factors. It should generally be the goal to program your dosers or calcium reactor to not require adjustment from day to day. If your tank is full enough and healthy enough, with sps growing very fast with a heavy bioload, you should be testing alkalinity every day or two. You can adjust your dosers or reactor every couple days to keep the same number all the time. To be honest. For me. I’ve actually had the best results most recently by adjusting my reactor strength to achieve an alkalinity of 7.5 dkh, and not touching it again until alkalinity falls to 6.5. I got this idea from JDA, and it has worked beautifully. Previously when I would make minor adjustments to try to KEEP it at 7.0 all the time I would end up over or under shooting it by 0.1-0.2 every single day meaning my alk was bouncing around like a ball. Growth improved dramatically when I stopped chasing the absolute. Of course if you’re into the bleeding edge of technology and like spending a ton of money, you can buy one of the several new options of automatic devices that test daily and adjust the dose on the fly for you. I’m still not sold personally. Different argument but I tend to prefer the natural and more complete and balanced mineral profile of a properly tuned calcium reactor even if it means doing things a little more manually Sent from my iPhone using Tapatalk Pro |
07/21/2018, 01:41 PM | #3 | |
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A few thoughts... Think goal posts not bullseye. The advice to avoid chasing numbers usually occurs when someone obsesses about maintaining a set value for a parameter. The overly concerned aquarist wants to hit bullseyes. Besides being difficult and expensive, there aren’t many bullseyes in nature anyway. Plants and animals can tolerate a range of conditions within limits. Staying within those limits where your creatures can thrive is an easier and smarter goal. How quickly changes can occur within those limits depends on the creature’s adaptiation capabilities. The definition of sudden changes within these published limits or ranges is what we need to define. I would guess that sudden changes (less than an hour) in pH, salinity, and certain ions, maybe Mg2+ Ca2+ should be avoided. Any system parameter drifting from a high value to a low value within its acceptable range in a day might be OK. We need a coral expert here to elaborate on how various species respond to changes in various parameters. |
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07/21/2018, 01:48 PM | #4 |
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My soft coral ranged from about 11 dKH just after dosing to about 7 dKH just before dosing. The corals didn't care, and the coralline was growing more than was required. What's in your tank?
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07/23/2018, 08:50 AM | #5 |
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Thank you guys for the replies. I have more SPS than LPS. My goal is to keep dKH between 7.7-8.1. I wanted an idea on what is an acceptable swing day to day.
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07/23/2018, 09:08 AM | #6 |
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The acceptable swing for your tank may vary from others. You'll have to determine at what low and high values work for you.
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07/23/2018, 02:46 PM | #7 | |
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I target 7.8-8.0 and have found that a shift of .5 per day does not have much impact on my coral, but if it swings back and forth I will get some RTN
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Gary 180 gallon, 40 gallon sump, 3 250 W MH + 4 80W ATI T5's, MTC MVX 36 Skimmer, Apex controller Aquamaxx T-3 CaRx Current Tank Info: A 2 Barred Rabbitfish, Red Head Salon, Yellow/Purple, McMaster Fairy, Possum, 2 Leopard Wrasses, Kole, & Atlantic Blue Tangs, 2 Percula Clown, 3 PJ and 1 Banggai Cardinalfish , Swallowtail, Bellus and Coral Beauty Angels |
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07/23/2018, 09:57 PM | #8 |
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I suspect a 1 dKH range is fine, but we don't have much in the way of useful data.
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07/24/2018, 07:09 AM | #9 | |
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I have a small softy/LPS tank which uses about 0.3 dKh/day. After a 5 gallon WC, my Alk is about 8.9 dKh. By the time of the next weekly WC, my Alk will be about 6.8 dKh. So, I thought my options would be: 1. start dosing Alk 3 days after WC, or 2. change the salt mix to the one which would give a higher starting Alk, or 3. do larger WC, say 10 gallon, to increase Alk, or 4. do nothing because the zoas and LPS should be fine with 6.8 dKh. What do you guys think would be my best option? I'm just trying to be more "stable". |
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07/24/2018, 09:02 AM | #10 |
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System is consuming roughly 2.1 dKH weekly, I'd say it's time to consider dosing. Swinging that much constantly won't be changed by doubling the WC volume. Increasing the frequency of water changes will, but do you really want to be changing water twice or three times weekly. I think not.
This is where a doser and 2-part solutions come in.
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07/24/2018, 06:41 PM | #11 | |
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I do have BRS 2 parts, but not a doser. Just trying to keep things simple and find the system sweet spot. Thanks for your feedback. |
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07/25/2018, 04:26 AM | #12 | |
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