Comparison

ACV Viper vs ReefATLAS PAR Estimator

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

ACV Viper

Features
Read full description

ACV Viper is the culmination of inspection tools and machine learning capabilities at ACV Auctions, car inspections, marketplace. These are packaged into a single platform as a dealer appraisal and inventory assessment tool. Our goal is to bring these technological advancements into the hands of dealers and industry professionals, allowing them to capture a wide array of vehicle information with the support of machine learning. This results in the most comprehensive suite of vehicle assessment capabilities in the industry.

About

ReefATLAS PAR Estimator

This app helps reef aquarium enthusiasts estimate and visualize light distribution without a PAR meter. It allows users to input tank dimensions, lighting equipment, and water conditions to predict PAR levels and make informed decisions about coral placement and lighting setups. The tool offers interactive 3D visualizations and supports a wide range of popular reef lighting systems.

Highlights
  • Interactive 3D PAR heatmap visualization
  • Support for popular reef aquarium lighting systems
  • Multi-fixture light array setup
  • Fixture placement and angle controls
  • Spectrum and intensity adjustment tools
  • Custom tank dimension configuration
  • Surface agitation and lid modeling
Features
Read full description

ReefATLAS PAR Estimator is a subscription-based aquarium lighting analysis app built for reef keepers who want a smarter way to estimate light levels without always having access to a PAR meter. Designed for reef aquarium hobbyists and professionals, ReefATLAS PAR Estimator helps predict and visualize PAR distribution using tank dimensions, lighting equipment, mounting height, spectrum settings, fixture intensity, water conditions, lid transmission, surface agitation, and other key variables. The goal is simple: help reef keepers make better lighting and coral placement decisions before guessing, moving coral blindly, or copying someone else’s lighting schedule from a different setup. FEATURES • Interactive 3D PAR heatmap visualization • Support for popular reef aquarium lighting systems • Multi-fixture light array setup • Fixture placement using a top-down tank layout • Support for mixed light models in the same setup • Individual fixture height, position, rotation, and angle controls • Master/slave light grouping for linked fixtures • Spectrum and intensity adjustment tools • Manufacturer-style spectrum presets where available • Custom tank dimension configuration • Manufactured tank catalog support • Glass thickness and internal dimension calculations • Surface agitation / shimmer adjustment • Lid type and lid cleanliness modeling • Salinity-aware estimate adjustment • Project save and load functionality • Local device-based project storage • Optimized for reef aquarium planning and coral placement SUPPORTED LIGHTS ReefATLAS PAR Estimator includes modeled profiles for many popular reef lights, including AquaIllumination, EcoTech Marine, Kessil, Red Sea, ReefBreeders, Maxspect, Fluval, Illumagic, REEFi, Orphek, Philips CoralCare, NavaReef, Noo-Psyche, GHL, Current USA, and more. View the current supported light list here: https://thereefatlas.com/par-estimator-lights New lights and tanks are added regularly. If your light or tank is not listed, the app includes request buttons so you can send it in for review. Requested lights are prioritized for modeling when enough manufacturer/spec/PAR reference data is available. HOW IT WORKS Configure your aquarium dimensions, select your lighting equipment, adjust fixture placement, mounting height, spectrum, intensity, water conditions, and lid settings, then generate a 3D PAR distribution estimate throughout the aquarium. For single-light setups, quickly model one fixture over your tank. For advanced systems, the Light Setup tool lets you place multiple fixtures across a top-down tank grid, including mixed models, different mounting heights, fixture rotation, and angled mounting. The estimator calculates each fixture’s contribution at each point in the aquarium and combines overlapping light output to create the final PAR estimate. This helps represent real-world multi-light setups where beams overlap, spread, and converge across the tank. IMPORTANT ACCURACY NOTE ReefATLAS PAR Estimator is an estimation tool. A real PAR meter will always be the most accurate option for measuring your specific tank. However, many reef keepers do not have access to a PAR meter. This app is designed to provide a better starting point than guessing by combining modeled light profiles, tank dimensions, fixture placement, spectrum settings, mounting height, water depth, lid transmission, salinity, and surface agitation into one interactive estimate. Accuracy depends on available fixture data, setup inputs, and real-world variables such as rockwork, coral shading, water clarity, lens condition, and surface movement. SUBSCRIPTION REQUIRED ReefATLAS PAR Estimator requires an active monthly subscription to access and use the app. A subscription purchase is required to use the PAR estimation tools and features shown in the App Store screenshots and description. Privacy Policy: https://thereefatlas.com/privacy Terms of Use: https://thereefatlas.com/terms

Screenshots

ACV Viper4 screens
ReefATLAS PAR Estimator4 screens

Verdict

The call

The clearest difference is in-app purchases: ACV Viper at none against ReefATLAS PAR Estimator's 1. ReefATLAS PAR Estimator's advantage is update cadence (daily vs fortnightly) and iOS requirement (14.0 vs 17.0). On price, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. ReefATLAS PAR Estimator sells 1 in-app purchase, starting at $4.99 per month. ACV Viper asks for nothing beyond the download.

UpkeepUpdate frequency

ACV Viper ships an update fortnightly, ReefATLAS PAR Estimator daily. The most recent releases landed on October 16, 2026 and October 19, 2026 respectively.

Scorecard3 real differences · 6 level
ACV Viper versus ReefATLAS PAR Estimator: the parameters behind the verdict, then further details
ParameterACV ViperReefATLAS PAR Estimator
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyFortnightlyDaily — better
AdsNoNo
In-app purchasesNo — betterYes
Monetization—Subscription
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.014.0 — better
Further details — not scored
Size190 MB27 MB
Age rating4+4+
DeveloperACV Auctions IncJONATHAN ALBERT PITTMAN

In-app purchases

None

ACV Viper

No in-app purchases

1 purchases

ReefATLAS PAR Estimator

Subscriptions1
  • ReefATLAS PAR Estimator Monthly$4.991 Month

Questions

Is ACV Viper free?
ACV Viper is free to download, with no in-app purchases.
Is ReefATLAS PAR Estimator free?
ReefATLAS PAR Estimator is free to download, with in-app purchases available.
Do ACV Viper or ReefATLAS PAR Estimator have ads?
Neither ACV Viper nor ReefATLAS PAR Estimator shows ads.
Which is updated more often, ACV Viper or ReefATLAS PAR Estimator?
ACV Viper ships an update fortnightly, and ReefATLAS PAR Estimator daily. Most recently, ACV Viper was updated on October 16, 2026 and ReefATLAS PAR Estimator on October 19, 2026.

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