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"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty
"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty

"Red Flex 4-in-1 300" Complete Four-Stage Filtration Sump System (37"L x 14½"W x 16"H┃Limited Lifetime Warranty

Brand: Pro Clear Aquatic Systems
Item Number: PCAS-373000

Regular price $559.99 On Sale

Only 5 left in stock!

Estimated Arrival: Between Jan 26 and Feb 01. *ETA for USA only. For accurate lead times, call us at 727-214-7750

Large, Custom, Or Backorder: Arrival Times May Vary.

Shipping Policy: Little or No Shipping Charges for Regular-Sized Items; We Cover Part of the Freight Costs for Large Items Shipped Nationally. See Shipping Policy.

Full Sump Dimensions: 37"L x 14½"W x 16"H

Skimmer Compartment Dimensions: 11½"L x 12½"W

Water Bypass Channel Dimensions:  8"L x 3"W

4-in-1 Compartment Dimensions: 8"L x 11"W

Return Pump Compartment Dimensions: 6⁵/₁₆"L x 12½"W

Suggested Flow Rate: 1200 GPH

Intake Size: 1"

Material: U.S. Manufactured Extruded Acrylic


  • Adjustable Flow Gate
    • Allows sump water level to be finely tuned for skimmer height or as a return siphon overflow buffer
  • Water Bypass Channel
    • Entire system water volume flows through this channel
    • Can use the least amount of media for the largest possible volume of water filtered
    • Chemical Media Cartridge available to hold various forms of media in vertical orientation for maximum surface area, water flow coverage, and easy media changeouts
  • Bubble Diffusers
    • break up air pockets and microbubbles to allow water to flow completely silent
    • Especially useful in living areas like living rooms, dining rooms, or bedrooms where low sound is a must
    • See 3rd video in "Videos" tab for an an example of these whisper quiet diffusers
  • Sock Chamber Overflow
    • Allows water to flow down into the skimmer compartment in the event of filter socks becoming partially or fully clogged
    • Prevents potential sock compartment overflows (which if the pump is still running, could potentially overflow 50% or our entire system water capacity
    • Additional fail-safe to keep our minds at ease when we inevitably forget to do a sock cleaning
  • Heater Holder
    • Don't have to rely on cheaply made suction cups to keep heater attached to sump wall
    • Heater stays put, and doesn't float around to heat up and possibly damage other in-sump equipment or media
  • 4-in-1 Compartment
    • Can be used as a wet/dry filter, refugium, frag grow-out station, fry grow-out station, and the list continues
    • Possibilities fueled by our creativity (we still hear of new uses for this compartments by inventive hobbyists)
  • Lifetime Use Ready
    • Every single Red Flex Sump is manufactured from U.S. made extruded acrylic, and crafted in Jacksonville, Florida
    • Built to last a lifetime of the most demanding use
    • Backed up by a Limited Lifetime Warranty. If anything happens, let us know and we'll make it right
  • All-in-One Sump Filtration Sump
    • Stylish and affordable solution for an all-in-one sump system
    • Not just a sump body
    • Everything needed to start up is included (see "What's Included" below)
    • Just add a return pump, skimmer (for saltwater), media, and plumbing for a fully functional and flexible filtration system

Setup and Assembly: 

  • See the "Videos" tab for a Video Tutorial
  • See the "Downloads" tab for the Red Flex 4-in-1 Assembly Guide

What's Included:

  • (1) Red Flex 4-in-1 300 Acrylic Filter Body
  • (3) 4" Diameter 200 Micron Filter Socks
  • (2) 1" Red Inlet Pipes
  • (2) Bulkhead Spacers
  • (2) Bulkheads
  • (1) Filter Sock Compartment Intake Cover
  • (1) Red Cord Restraint Bracket
    • (2) Nylon Screws
  • (1) Dosing Spacer
  • (4) Dosing Quick Connect Fittings
  • (4) Color-Coded Dosing Connectors
    • Red
    • Blue
    • Green
    • Black
  • (1) White Frag Rack
  • (1) Red Hose Restraint Bracket
    • (2) Nylon Screws
  • (1) Foam Block
  • (2) Grey Flex Hoses

      Below is a video of the Pro Clear Team providing a full and detailed Setup Demonstration Guide of the Red Flex 4-in-1 Sump. Thanks guys!

      Our good friend Billy Pipes was nice enough to give us permission to use a few of his review videos of the Red Flex Sumps he received from Pro Clear. Follow along with him as he walks through every feature of these revolutionary sumps as well as he explains how he will be incorporating them into his existing systems.

      Of course, all credit for these videos goes to Billy, and to show some thanks for his generosity, check out the rest of his channel here and subscribe if you enjoy his content (we highly recommend it because he puts out consistent killer content).


      Additionally, here is another video by Billy that showcases how whisper quiet Pro Clear's patented bubble diffusers make their Red Flex Sumps. Bubble diffusers come standard with both the 4-in-1 and Reef version of these sumps.

      Below is a Setup and Assembly Guide for the Red Flex 4-in-1 Sump.

      Red Flex 4-in-1 Setup and Assembly Guide


      The Red Flex 4-in-1 is a convertible sump that can be easily changed from saltwater to freshwater and features a four part filtration cycle all in one sump. It features a modern and durable red and white reinforced acrylic design, and it is packed with loads of new, innovative features to make your marine experience as hassle-free and enjoyable as possible.

      Full Sump Walkthrough

      Filter water from the display tank begins its journey by flowing through the two bulkhead ports and into Pro Clear’s patented bubble diffuser silencers. The water then overflows over the top of the silencer and moves through the included 4 inch 200 micron filter socks (1 is included with this sump).  Each sump includes an overflow panel in the filter sock compartment where the water can escape into the next chamber if your socks happen to clog and overflow.

      In the skimmer compartment, the Red Flex includes a heater holderprobe holderswire holders for the probes, and color coded dosing lines. The dosing lines come with blue, red, green, and black lines so you can easily coordinate what you are dosing in which line. All of the holders are easily maintained and adjusted by built in fasteners.

      From the skimmer chamber, the water then flows past all probes and dosing lines and then makes its way into the Chemical Media Canal. This canal is used to house the media of your choice. Within the canal you have the option to use Pro Clear’s unique Chemical Media Cartridges specifically designed for this area to house various forms of media in a compact, easy to remove, and easy to clean container (Chemical Media Cartridges are optional and not included).

      Once the water reaches this area, you have the option to allow the water to flow into the refugium section or straight into your return compartment via an adjustable flow gate. The refugium has a built in frag rack with two position options, one at the very top of the chamber and one in the middle of the chamber. The refugium area is blocked off by a removable panel at the bottom of the chamber which can be detached to allow the water to more easily enter the return area. If the removable panel is left attached, water will fill up the refugium chamber and will overflow over the top and into the return pump area.

      What’s Included

      All Red Flex sumps include flexible hoses4 inch 200 micron filter socks and a foam block sponge for in between the refugium chamber and the return pump section.


      Because of Pro Clear’s long lasting and consistent build quality, Two Tides Aquarium Supply offers a Limited Lifetime Warranty through Pro Clear Aquatics on all of their sumps. You can have peace of mind that if anything goes wrong at any point down the road, we have you covered. 

      Keep in mind that you will have to fill out Pro Clear’s Warranty Registration Form on their website no later than 15 days after the purchase date. But don’t fret! There are plenty of easy to follow instructions for filling out the form as well as details for what the warranty covers in the “Warranty” tab above.

      Sump Warranty

      All Pro Clear sumps purchased through Two Tides include a Limited Lifetime Warranty on defects in manufacturer workmanship such as leaks or cracks. This includes all Red Flex Sumps, EcoReef Sumps, and Premier Wet/Dry Filters. Please note that coverage under warranty can only be granted to the original purchaser.

      See "Warranty Coverage" below for how to register for your Lifetime Warranty.

      Tank Warranty

      All Pro Clear tank systems purchased through Two Tides include a 36-Month Limited Warranty on defects in manufacturer workmanship such as leaks or cracks. This includes all ProStar and Acrylic Cylinder Aquarium Systems. Lighting systems and pumps are covered under a 12-Month Limited Warranty if included. Please note that coverage under warranty can only be granted to the original purchaser.

      See "Warranty Coverage" below for how to register for your 36 Month Warranty.

      Warranty Coverage

      Click Here to Register for Warranty

      The Two Tides warranty through Pro Clear Aquatic Systems protects against any leaks that occur during the warranty period due to manufacturer workmanship. If such a leak occurs, a new and fully functional product will be sent out to the customer immediately.

      This warranty also covers any small part breakages or failures. If a part happens to break or fail within the warranty period, either replacement parts or an entirely new product will be sent to the customer. Instructions will also be sent to the customer for how to properly and safely install replacement parts.

      Photos of damages or failures as well as a throughly detailed explanation may be required to be provided to Two Tides before we can process a warranty claim and send a replacement product. This is especially important in the event of cracks or other more serious damages.

      Shipping, Cancellations, and Exchanges 

      If a Pro Clear product is purchased before noon on a business day, it is generally shipped out the same day. If a purchase is made after noon on a business day, it is generally shipped out first thing on the next business day. 

      Because of this very short order to ship out time frame, cancellations must be made within the first few hours of product order, and FULL refunds, although mostly fulfilled, are not guaranteed (because of labor time, the fact that the product may already be fully packaged, and that shipping arrangements may have already been made). As a general rule, if it has been more than a half to one full business day from the order date or if a tracking number has already been created, then the order is unable to be cancelled. To ensure you get a full refund if you decide to cancel an order, email us ASAP at

      In general, exchanges are not accepted for Pro Clear products and are not an option under warranty. Replacement products/parts are the usual option to go with.

      Warranty Questions

      If you have any questions or need clarification on the above mentioned warranty information or need to submit photos and a written explanation of damages/failures, contact us at We'd love to hear from you!

      Warranty Registration Form

      Customer must have filled out the online Warranty Registration Form for Pro Clear (linked below) within 15 days of the original purchase date to be able to claim this warranty. This will grant the customer an Entry ID Number which will be needed if the customer ever decides to file a claim for their warranty.

      • Click Here to Register for Warranty
      • It is strongly recommended that the customer fill out and submit the Warranty Registration Form directly following purchase to ensure there are no issues if a warranty is claimed later. We will send you emails about this to remind you.

      Steps to Filing Warranty Claim

      1. Make sure you have filed a Warranty Registration Form online (linked above). Note that if this form is not completed and submitted within 15 days of purchase, the warranty will NOT be eligible. This form will provide you with an Entry ID Number. Once this Entry ID Number is distributed, the Lifetime Warranty is then in effect.
      2. Email Provide a brief explanation of the issue with your item. Some examples may be, “The product/package was damaged when I received it (and what types of damages)”; “The product doesn't work properly/as advertised”; “Parts were missing”; etc. Your email should include the following information:
        • Name:
        • Address:
        • Contact #:
        • Email:
        • Product name & item #:
        • Entry ID# (provided at warranty registration)
      1. From there, a representative from Pro Clear will be in contact with you to walk you through the rest of the process.

      Keep in mind that all warranty claims are at the discretion of Pro Clear Aquatics. If you file a warranty claim, that is not a guarantee that it will be accepted.

      As always, if you need any clarification or if there’s anything else we can help you with, please don’t hesitate to reach out to us at

      Have any further questions that aren't answered here? We'd love to hear from you, and learn how we can help you be as successful as possible in this wonderful hobby.

      You can call in to 727-214-7750 to speak with Tyler from our team to determine how to create your Ideal Aquarium Build.

      Also feel free to reach out to us at and we will aim to respond back within the next few hours.


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      Customer Reviews

      Based on 1 review
      Pro Clear 4 in 1 Red Flex Sump

      Hey Andrew,

      Absolutely, very glad we could resolve the leak and get your system goin before the weekend. Gotta love the contrast on that stand you made.

      Let us know how the cycle on the new tank goes and talk soon.

      To Your Success,
      - The Two Tides Team


      ★ Read Reviews of Two Tides

      The Proof is in the Result

      27 reviews

      So...late one night I was shopping online for a new seahorse tank. I ended up on the Two Tides website & in the bottom corner it said to click for a live chat. Since it was after midnight & they’re in the same time zone, I thought no way. But I clicked anyway & sure enough I was chatting with a live person! We chatted for over an hour until he asked for my email address telling me I’d be contacted the next day. That’s when I met Tyler. He helped me with my purchase. He went above & beyond to get me the tank I wanted, even spending a day on a video chat with Pro Clear Aquatics as they searched their warehouse looking for the aquarium I wanted with a blue back. They stopped making these a while back but they found one for me! I absolutely love this aquarium & I can honestly say that Tyler provided THE best customer service I have ever experienced from an online vendor. He told me from the start that he would stay with me from start to finish & he did. He was always there to promptly answer any questions or concerns I had. I can’t say enough about how happy I am with my purchase!

      Piece of Art

      I was looking for rimless peninsula aquarium to upgrade my 80 Gallon and my 70 Gallon mixed coral reef this year, but had a really hard time finding it because of the coronavirus. So I purchased a ProStar 230 Peninsula from Two Tides and I’m glad I made the right choice. The 3/4” low Iron glass display tank and large glass sump and light weight white stand is just beautiful as a piece of art. Tyler is extremely helpful and responsive and made the process easy and stress free. Everything arrived very well packaged. When we were setting up the tank, we couldn’t believe how easy the setup was with no issues what so ever. If you are looking for a high quality aquarium I highly recommend this company.

      Absolutely beautiful fish tank and customer services

      I am very happy with my order. The tank is very beautiful of out the box and it was well packaging with feel very safe from shipping damage.

      Custom services from Two Tides Aquarium Supply was excellent. I have communicated with Tyler who had assisted me throughout the process from ordering the tank through shipping process, and what to expect on delivery day.

      I am highly recommend anyone who want to get a new aquarium, to purchase from Two Tides Aquarium. Best to look for Tyler, he is a very helpful and pleasing person to contact if you have any question. I am glad that I have met him and definitely I would buy again in the future from Two Tides Aquarium supply when I need another fish tank and any other aquarium supply that I may need.

      Thank you very much for a beautiful tank.


      Great Customer Service

      I am very pleased with not only the product I received but the service that came with it. Tyler was in constant contact with me throughout each stage of the process. He answered all questions I had and was even able to provide me with links to plumbing parts I needed for the build. We had a small hiccup with shipping (carrier's fault not Two Tides) but Tyler was able to update me throughout the day. Tyler genuinely cares about his customers and I would recommend the company to anyone looking for their next show room tank!

      Great unit

      Makes water quickly. Very happy with the unit so far. Pump is quiet, runs great. Finally decided to get a good rodi system. This one has exceeded my expectations way better then any other unit that I've had before. TwoTides Aquarium supply shipped it fast and couldn't be happier with this unit.