How Do I Setting Up A 20 Gallon Salt Water Tank

Brok3n

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I have a fluval 20g saltwater all in one tank. I’d like to set it up with something simple like one fish and a shrimp, possibly some coral. I’ve measured the light in the tank and it reads 100 PAR at the base. I have experience maintaining two 57 gallon freshwater aquariums. I’m familiar with the chemistry that comes along with keeping fish. What I’m curious about is white shrimp, fish, coral combination I can keep that will be very low maintenance. I’m hoping to limit the water changes to once a month once it cycled.

For example I know that I’m very fond of blood red shrimp. This is because of their size and vibrancy. So one suggestion I’m looking for is what kind of single fish should I include if any. I’m specifically looking for fish I can feed it with an auto feeder.


Thank you
 

stella1979

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Hi Sorry, but I gotta say, this is a big ask... Once per month water changes and auto-feeding brings to mind excess nutrients and a resulting algae garden. Add to this that many corals are unhappy with elevated nitrates, (I'm talking like, over 15ppm), as can be sensitive inverts like the shrimp you've mentioned.

However... there are things reefers can do to reduce the excess nutrients in the tank, though these nutrient reduction methods also take their fair bit of attention and time, which it sounds like you are short on. Anyhow, examples of nutrient reduction methods are the use of refugiums (which we may be able to incorporate into the chambers of your all-in-one), skimmers, (can't go cheap here since in general, small skimmers that are also cheap are... well, cheaply made so may not do the job they're intended for, or worse, cause you headaches), and specialized chemical media made for reducing phosphates... nitrates and phosphates are the favorite foods of algae.

Okay, so a refugium... all you need here is a place to grow macroalgae, usually chaetomorpha. You must light the refugium for growth of the chaeto, and the chaeto will uptake nutrients for its growth. The trouble is, portions of the chaeto must be removed from the fuge regularly, particularly if you have little space to grow the chaeto in the first place. In nano tanks, we generally have little fuges... I'm imagining your's in an inner chamber, while my fuge is in an Aquaclear 70 HOB. (Btw, I have a 20g long nano reef tank.) When the chaeto grows to fill the space, then runs out of room, parts of the mass will die. If chaeto dies in the system, it dumps all those nutrients it ate up right back into our water. Nutrients come from organic matter, so this organic nutrient reduction method has its own drawbacks... I suppose. Never thought of it that way myself but I am available to manage my fuge, so it works.

I also use chemical media called Chemipure Elite, which reduces phosphates.

I do not use a skimmer and all I can advise in this arena is that you get what you pay for and that a well-tuned skimmer can do an excellent job at removing organics before they break down into nitrates and phosphates.

You probably know that all these nitrates and phosphates come from feeding our tanks but I'll tell you what... I do not feed every day and I do do 20% water changes every week like clock-work. In fact, due to algae issues in the not too distant past, I rarely feed the fish more than 3 times a week and hardly feed corals at all, (not feeding corals, having seen the growth boost that comes with regular feedings... well, it's not fun.) I have 3 fish, one shrimp, a few snails and hermits, and lots of coral. Given the feeding and water change regimen, you'd think that I wouldn't have algae woes but I'm dead serious when I say, if it weren't for the fuge, the Chemipure, and further nutrient reduction done by twice weekly cleaning of mechanical media... then I wouldn't have happy corals, I'd have an algae garden.

Hmmm, you didn't mention how you'll supply saltwater for the tank, so forgive me if you know this already. We do not use tap water to make saltwater, we use very pure water instead. Having a RODI filtration system is a very good idea for all saltwater tanks, and in most reefer's opinions, a must for corals. Marine fish tend to be much more sensitive to water quality than many of their freshwater counterparts, and corals will absolutely not tolerate anything in the water which is not found in the oceans. If you think about it, though pollution is a very real thing, the ocean's are vast so dilution is great. The tiny bit of something like heavy metals (copper for example) that may be in a tap source is not harmful for humans, our land-lover pets, nor most freshwater fish... but your salty fish might be harmed and with sensitive corals and inverts, using tap water is a big risk. I should say, advice against using tap water is VERY common in the reefing community, and for good reason, but municipalities with very clean tap water do exist... though I do think this is quite rare.

Sorry to seem so down on your plans. I do have advice to move forward given your requirements. I'd recommend a fish with a very light bioload so... maybe a firefish, or perhaps something that'll eat a little algae like a tailspot or lawnmower blenny. Start this tank as a FOWLR, that is, fish only with live rock... no coral. See how it goes as far as the water quality you can provide, the nitrate and phosphate levels you get with an auto-feeder, and if you can keep a fairly clean tank. Speaking of the auto feeder... I've no experience there but always thought these were best on large well-stocked tanks. Can you use an auto feeder to feed just a few pellets, which is all a single small fish will need?

If you can get a RODI system and make your saltwater, really, really great... If you can buy RODI water and use that, great (though you'll want to check your source/the RODI regularly, using a TDS meter and RODI water should be absolutely pure, so no dissolved solids, so the Total Dissolved Solids reading should be zero), if you can buy RODI and saltwater from an LFS, maybe great (because you don't know how well they maintain their filtration system, there is a risk here). Also, please know that a saltwater tank requires saltwater for water changes but it also requires fresh (pure) water for topping off.

As a saltwater aquarium loses water to evaporation, well, you probably know that everything in the water is left behind... including salt. Salty tanks require freshwater top offs every day, or your salinity will rise and inhabitants will die. All is not lost though. You may purchase an automatic top off unit, aka, an ATO. The ATO will use a reservoir to deliver RODI to your tank in small increments daily, so the tank will not experience fluctuations in salinity. Personally, I had the reef tank running for a year without an ATO and during that time, I was a slave to topping off every day. With a glass lid, my 20g could evaporate up to a quart of water per day, though normally, it would be closer to 2-3 measured cups. So, every day, once a day, I'd gather that amount of RODI and slowly pour it into the tank. Things were okay but occasionally corals would get mad at this sudden, (though seemingly small), fluctuation. Mad corals are no fun and I honestly believe periods of upset can slow growth. All this to say... my tank is happier with the steadier salinity made possible by the ATO... and, lol, I can go on vacation without worrying about salinity, yay!

Sorry for the book... I'm known for looong posts around here. I hope this helps or at least gives you some things to think about moving forward. I'd certainly like to help you get your feet wet and salty, so do feel free to keep the questions coming. In the meantime, here's a great article on starting a nano reef tank.
https://www.fishlore.com/aquariumfishforum/threads/narts-budget-nano-saltwater-guide-for-beginners.327674/#post-3398686

And, eeek, here's a thread illustrating the downfalls of using an inferior water source.
https://www.fishlore.com/aquariumfishforum/threads/rodi-vs-non-rodi-water-in-pictures.330397/#post-3425802
 

Brok3n

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Thank you for the advice! I mention the auto feeder only if I go on vacation for a couple days. I just wanted the flexibility of not having to provide frozen meat or other live food. You bring up many salient points!
 

Jesterrace

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I have a fluval 20g saltwater all in one tank. I’d like to set it up with something simple like one fish and a shrimp, possibly some coral. I’ve measured the light in the tank and it reads 100 PAR at the base. I have experience maintaining two 57 gallon freshwater aquariums. I’m familiar with the chemistry that comes along with keeping fish. What I’m curious about is white shrimp, fish, coral combination I can keep that will be very low maintenance. I’m hoping to limit the water changes to once a month once it cycled.

For example I know that I’m very fond of blood red shrimp. This is because of their size and vibrancy. So one suggestion I’m looking for is what kind of single fish should I include if any. I’m specifically looking for fish I can feed it with an auto feeder.


Thank you
This might help you along your way as it explains the differences between the two sides of the hobby:

 
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